I have never tried alphas with my assy speed fins where I run the first leg on the wrong tack. All my assy speed fins tend to get a bit sketchy over low 30's knots on the wrong side and they are not going to accelerate out as well on the wrong side either.

I think you definitely would have gone faster on a symmetrical fin. Your board will crab more on the wrong side with an asymmetrical and this is bound to slow you a bit..

Are you talking weed fins or upright fins? Some of my best Alphas were done at Lake George on my IS-50 with the Lessacher 22cm (double assy) duo rake 30. The same setup I used during my PB 1hr run. At Sandy Point, where weed is not an issue, my best runs have been with the TM-26 (Alpha) and Lessacher 25 Duo Rake 30 in my IS-87.

At Fangys, I remember I got a couple of good ones on my CA40 with symmetrical Vector 19cm (40 degrees) weed speed, in that lovely, super smooth weedy concoction you have.

I choose the side of my assy delta to increase the foil for exactly the same purpose. I figured that the time I really needed the lift on a bigger delta was coming out of a gybe on an alpha attempt here. I chose the bigger fin on the basis that I wouldn't be going for top speed, so early lift was more important than drag. So I think we can say that you are correct as soon as I rack up alphas like Grumpynuts and Stroppo.
(assuming that bolting the fin on the roof racks and doing 180's around the big roundabout coming into town counts)