Everytime I toy with the idea of making my own bait I look at this basemix lol, I've not used it though as I always conclude I haven't got time after researching everything
but BAF products are usually good quality, I've used the liquids quite a bit their liquid liver is a bit good and the fish hydro and a yeasty one too, I would use those with confidence.
If I was going to use it though I may start off just using it as it is, but maybe just use your own flavour liquid combo as suggested by JB, then you could just tweak if you needed too after, but if you start off adding bits you may just be making it cost more without needing too,
Might be worth joining the homemade bait buffs on FB though, they should be able to put you in the right direction