Some the pipe tobacco flavors are too much. Am4A I would only be able to use at such a low concentration it wouldn't clog/gunk anything. A lot of these flavors are really strong. Seems to me 3% of SC flavoring could take your head off. Tobaccos can be the best for light flavorings where nothing sticks out, to get tired of.
I need to try more Stixx Mix flavors, but I see Nic Riv doesn't carry them and the price has gone up. Actually, what is happening with tobacco extracts? I recently had to order from Ina in Poland to get my mandatory TAs. I use natural flavors to add that "natural" sort of taste a lot of the time, at low strength.
My favorite synthetic(?) base is Hangsen Virginia, but I don't really like their RY4 etc. Decent by itself but I mostly use .1-.3% plus something else. For example Purilium Sweet Tobacco .3% (3 drops in 25 ml), with .2 HV.
Some hits and misses:
TFA M-type - useful but requires predilution as you don't want to exceed 1 drop per 100 ml.
INA/TDM 555 Gold and French Pipe -- sometimes useful basic flavors. The 555 is very nutty and I've superceded its use with Pur Sw Tob.
SC Cohiba -- about as pipe-y as I can go. Very good.
TFA Western -- wonderful intense except it gets old, stale tasting in 3 days.
TFA Turkish -- promising but kind of strong, I haven't messed with it much.
FA Virginia and 7 Leaves -- extreme floral note, adds a good hoppy top at .1%
FA Soho -- sort of dry but good RY4, actually needs a long steep (1 week).
TFA RY4D -- not spectacular but use it a lot
FA RY4 -- a little less sweet but similar
TFA RY4 asian -- good but caramel aftertaste. Seemed like a add to RY4s at first though.
TFA RY4 orig -- awful roses
INA Dark Tobacco -- good pipey
INA Maxx Blend -- weird, old shoe
Desert Ship -- weird/old shoe
FA Glory -- old shoe
dktab -- old shoe
capalla bold -- fizz