RE: Apollo Vs F161
The link above is to some pictures and blurbs about oversized Curtis / gSport formula fins that our local fin guru Dave Kashy experiments with. Pretty cool.
I think you can buy an 85 cm fin from gSport; www.gsport.com, under formula fins.
True Ames also sells 75 and 80 cm fins; http://www.trueames.com/wind_select.php?wind_products_id=12