I went the single route after Todd (TLR) recommended the setup. Same setup that Rick Roy was using........ I started with a plain mikuni 44. With that setup the power was really smooth and crisp..... I later picked up one of Todd's modified 44's where the bores the bottom side out to 48mm, with this setup my ski really hit much harder, downside, the power was twitchy, not something you want to cruise with..... Also, I did have to do more tuning, more prone to needing tweaking with weather changes. Got to be a pain, after a year I picked up a set of Team Scream modified 44's..... still running them 3 years later........
My thoughts, I could honestly run either setup, the duals give me better power overall plus I can cruise a tad bit better than I could with the single, the single drank gas like a slurpie..........
As far as the blackjacks, many here have had good luck with them, A close friend (Veteran racer - who holds a few national and world titles runs them in his Superstock/Open class ski) runs them but has said that they can be a bitch to tune, once tuned they are great.......... So, here is my take, if you are running Art's motor setups, use his recommendation and they will be great carbs. Use someone elses setup you may have a headache, but this can be true with any other carbs....... stick with the carbs that your engine builder knows what the tricks are........
I am gonna eat some crow here......... I have voiced my negativity towards them, still think they are harder to tune than others, but hey, who knows, I may run a set at some point, the price point on them is really nice.......