Uroy

you can spod a nice sloppy mix over the top, one that will have risers or neutral buoyancy bits (solar up and down mix) is probably the best and i prefer to add evaporated milk to mine to give a nice cloud to it.
Nige is probably the closest to a zig expert we have on here

My winter results are pretty dire tbh…… With the silt being quite deep, I'd probably do a mix of both dead and live maggots. Groats are a cheap particle that could be added, they kinda replicate maggots a bit, looks wise and will take on some liquid additives too... Good luck mate.
 

I’d not ignore putting out a good quality boilie. This is the time of year the fish go on the feed and put on weight. They’ll be searching for a good food source. Crumb it up and use halves to get it to settle on the silt. Don’t be afraid to fish in 3ft of silt. Just use a helicopter setup with a chod rig set 3ft up with a 1ft between the beads so it can settle nicely on top. 

Ive never used the kd rig as a pop up rig, I always used it critically balanced with fake corn but had the hair finishing at the bend of the hook which is usually 10mm to the bottom of the bait to the hook
My all time favourite rig and wouldn't use anything else for fishing over particles

I used to fish slightly longer rigs but find about 9" is the ideal for me.
I used to worry a lot about trying to keep the hookbait away from the lead, but concern myself more nowadays with matching the hooklength colour to the lake bed, swapping between weedy green or silt coloured depending on venue.
 

From 9 to 12 inches coated braid 
Uncoated braid 2 to 6 inches in bags 
Chods 1 to 6 inches 
Floating 1 to 4 foot 
Zig 1 foot to lake depth
 

Ive been looking at various rigs on line and it seems most anglers vary the length of their rig for various situations . 
Personaly I tend to use short rigs 4-6 inches . But I'm not sure why . It works (most times) but does any one favour longer ones and if so what determines you to use a longer rig ? The type of bottom ? To catch wary bigger fish?  
Any thoughts much appreciated 

Some interesting stuff there lads , cheers. My new water is very silty with tests showing a 1.5oz lead to be sinking in as much as 12 inches in places. I've switched to helicopter set up instead of standard lead clip set up and I've been using 6-8 inch hooklinks but I think I'll try 10 inch plus rigs and vary them over three rods to see if any are more productive than others 

You can ask miwillons  of anglers what length rig they use, and the answer is quite possibly between 6-9 inches from most of them, although Chod rigs will drop that average. Ooh err Missus
Some of it is watching Dvd's or blogs, and big name angler always uses that length, so 'you' copy.
There are absolutely loads of reasons to change rig length, how and what you feed, the amount you feed, the lakebed, how the carp feed, what they are used to dealing with, even the bait you use.
 
A few years ago now I was using a small lake near me as a test lake for various rigs, lead set-ups, baits and indication. At the time most anglers were still using 6-9 inch rigs, so I tied up a few, and cast them into a spot where I could see the reaction. Many of the carp would actually back off  (boilies mostly), 6 inches with baits in their mouth, freebies and hookbaits. So suck or pick up, back off 15cms, and then stop before spitting or swallowing. If a bait had a hook on it, you could watch them 'thinking', the eyes would roll, and with a semi-fixed lead, the carp would tighten up to the lead, so either back off, feeling for the lead and then with the weight of the lead, the sucking, blowing and lip movement could eject the hook, on even mega sharp hooks.
Now think about this, if the carp back off that distance, how can you confuse the issue? Lengthen or shorten...
Obviously not every carp could eject the hook, or you would never get any runs, but many do get away with it. Imagine what happens when you can't see it, and as much as I slate them, the Korda dvd's do show you how easy it is for the fish to get away.
 
My mate Al, on a small fish water we have been on recently has found the best length for hooked fish has been 30cms, or 12inches. Fishing next to each other he has been hooking 3-1 to my shorter rigs, and the carp are not massive either! 
 

I use longer rigs in silty lake beds up to 2' long depending on the depth of the silt....

I see your point, i worry about that too.
The only way it would slide down is if a fish was hooked and the bobbin pulled tight. I just re cast if i have doubts.
As for bottom bait i use this

Nothing complicated really, coated braid, micro swivel, size 6 chod, bb shot, putty away you go. Pretty much only rig i use 

No need for shrink tube bud. I tie my hook look so it just goes over the bend of the hook. Fish em quite short. Also i use a bb shot with a little putty. Neatens it up

Cheers mate . I've tested it in a basin and it sits well so just wanted some feed back as to wether or not it was as supposed to be 

Have you tried putting a foam nugget inside a small mesh pva bag along with your mix of choice?
As Nick suggests, don't compress the bag too much as you want the air in the bag, but for extra buoyancy and a secure hook hold, try putting a pva nugget inside the bag to one side, then push the hook point through that.

 

Well i use the heli setup with pop ups so on the hook is no good for me i normally tie my stick to the lead loop and put 2/3 foam nuggets in the bottom of the stick to keep it suspended as it sinks take that with a pinch of salt yet to land anything so far this season .

I think experienced anglers will always look to do a bit of stalking when they can, be it floaters or on the deck.
 
One thing I don't look at with rose tinted glasses is the rubbish tackle he uses, thank goodness that side has progressed, I'd give up if that was my set-up, useless.