I had similar thing on the last water I fished I found the below nailed them
Rig length around 5"
Hair length around 1.5"
ESP big T size 6
Using 18 mm bait
Shrink tuning slid up the hook and slightly down the rig from the eye so once steamed you can put a kick in it.
I'm presently fishing a new water and have so far had 7 fish fall foul to that rig on the new water so will be keeping it like that until I have any problems.
Its also important you check your hook point before every cast to make sure its as it should be I always add a bit of rig foam over the hook point to protect it on the cast and when it pops up it gives you a good marker as where to scatter your freebies. I have always done better on a large scatter of bait opposed to tight baiting up also worth you mixing it up with 10mm , 15mm , 18 mm boilies then it leaves you a nice choice as to what size you want the hookbait and using different sizes and scattering them keeps them occupied looking around
Hope that helps Best of luck next session