Yeah Dave I was chatting with Lance a few months back about their new system, similar concept to the pro box but without the insert to adjust cant. If I recall correctly they'll still have similar fore and aft adjustment. I imagine you'll be installing a set in the not too distant future

Chrispy they're like surfing on rails, really drivey but not at all tight. They seem to turn in a tighter arc than wide base fins and they load up and flex and really drive through turns. About the only thing they don't do is slide out, my top turns have gone from tail slides to hacks (when I actually make one) They accelerate out of turns too, kinda like when you down gear going through a corner on a two stroke dirt bike and powerband kicks in, takes a little getting used to.
I was having the same issues as you on bottom turns with quads as I like to really lean forward and lay into my bottom turn, these have the effect of moving your fin area back but retaining a loose feel due to the narrow base.
Grab a pair of the H3's as tail fins to try behind PC7's and if you dig them then get Lance to hand make you a pair of the front fins like my T2's or in his LS series. The front fins in mine are 5.5" high and the back are 4.75" quite a bit bigger than his standard sizes.
http://www.hanaleifinsystems.com.au/pages/fins/fin_series.htmlTell ya what if you grab a pair in FCS base off him and don't like them I'll buy them off you as I've been meaning to get a pair for my little fish and haven't got around to it yet.