Yeah, Flash definitely improves the TH. I always made a "pre-mix", at varying percentages, depending on my current nic level; I've used pre-mixes that were 20%, 30%, and 35% Flash, with sometimes about .5% sweetener, in PG; I'd use the pre-mix in my recipes at anywhere from 5% to 10% of the mix.
The pre-mixing I found necessary because the stuff is REALLY potent, and it's very easy to ruin a whole batch of ejuice if you use too much Flash; if it's too much, it will often cause coughing, from the throat "tickle", and it can also cause a lot of sneezing because it tickles your nose -- the active ingredient is piperine, the chemical that gives black pepper its zing... so it pays to use it carefully.
High-PG also improves the TH terrifically, if you can tolerate the PG; so many just can't. I personally use 4.5mg nicotine, 86.5% PG, and don't need the Flash anymore; I think you kinda lose your taste for that, the longer you don't smoke; when I started vaping I wanted TH to grab me by the throat and shake me around; now a mild tingle is fine, but don't really want anymore than what the 4.5mg and 86.5% PG can give me.
Andria
ETA: I also don't have the first clue about pre-made ejuice; haven't bought any in about 3 or 3.5 yrs... however, ECBlendflavors.com always did right by me. They mix to order and you can customize what you get with quite a few different options, but because they mix to order, steeping is usually necessary. Good prices, decent ejuice.
If you get to the point that you want to mix your own ejuice, I can highly recommend the Inawera Shisha Strawberry; tastes exactly like fresh strawberries sliced and sugared, and doesn't interfere with great TH.
