Update, and hopefully answer a lot of questions.
I tend to stick to dinner lady 70/30, occasionally use others but keep coming back to DL.
This week I've tried running on minimal W settings, so far so good, although at 25W, flavour is not he best. Max setting is 35W,I'd normally run around 30-32W.
I've also tried some higher 50/50 vg/pg which seems to leak like fuck but does allow lower W so should prolong the life of things