Topics tagged isomerization << read through these, tons of great info and discussion surrounding the subject
Cbd isomerization to d8 and d9 thc << Jeds tek was first mentioned here then split off into his own thread which has been linked in your citric acid post, but he quickly moved on to pTSA as it provides a much faster and more selective isomerisation (his goal being full conversion to d8)
it’s a little abstract and pretty low oral dose but ~50-75mg provided strong effects, very relaxing, heavy body stone/nice glow for around 5+ hours. No ill effects that i noticed during or in the days following.
I’ve not much to compare it too, distillate of any kind isn’t really a thing here, we have some BM carts floating around but I don’t trust them due to bad experiences with synthetic cannabinoids during the “legal high” days.
Compared to my 25% THC medicinal flower i’d say the distillate is much less “heady” and a lot more body intensive so i’d have to deduce high D8 content but still a very enjoyable experience and good for my needs (watching tv, wrapped in a blanket not wanting to move without a care in the world for hours then the sudden urge to eat all snacks in the house 
)
I just had a few bottles of 99.99% IPA lying around and ethanol is quite a bit more expensive, especially for high purity.
Sorry, i have no experience with sulphuric. Acid’s are very difficult for me to obtain, I think even acquiring 85% phosphoric has gotten me on a government list as after purchasing i found it to be on an explosive precursor watchlist at anything >35% and as of October 1st new legislation states it’s illegal to use/own/supply or import… carrying a fine and upto 2years imprisonment 
most other useful acids are covered under the dangerous weapons act due to gang/revenge related acid attacks years ago… my only options moving forward are to extract/purify from hardware supplies or synthesise although i have seen pTSA for sale on ebay in small quantities under it’s alt name tosylic acid and i found a source for Amberlyst 15h, ion exchange resin beads that ships to residential without chemical licensing requirements. so these are my two options looking forward but for now i’ll run the rest of my CBD in phosphoric
As for citric acid vs phosphoric… most of my citric acid experiments crystallised immediately upon cooling and were discarded. one stayed oily for around 24hours before small crystals started forming so safe to say the first few were mostly CBD and the longer hold out was partially converted. the small successful run i had with citric was definitely THC but not as potent as my first phosphoric run. When i weight the two reactions together, the time/energy input for citric just wasn’t worth continuing with although if you managed to work out a successful sop then ran a large batch it would still be a viable option. 2-3days for citric vs 8 hours from start to first pass distillate with phosphoric. there is a clear winner regardless of higher potency.