I mix it at 20% 70vg and find that just fine for me. I guess it comes down to taste, I do like a strong flavour tbh and still find 20% is enough, but if you want to edge your bets, there would be no harm going with 25% or even the suggested 30%.
I have tried the premade nice and it was very, very strongly flavoured, so I guess that explains the 30%, I still enjoyed though [emoji6]