Well, I have been at 32 meters in plastic Mares Avante tre and currently use Mares Razor Carbon with the stiffened part that goes into the footpocket (added a 0.5 mm carbon fiber layer). My major requirement for the fins - no cramps! I could swim 1000 yards butterfly kick no arms/no fins in 20 minutes and dive 50 meters butterfly kick no arms/fins so I believe your strength and technique are more important than the blade. Moreover those suggestions by manufacturers that the heavier you are - the stiffer the fins you need are wrong and dangerous. I am 118 kilos currently so I should know
Fins have to be medium stiffness at best, just larger people have to have a bit larger fins.
As far s Greek fins - I hear great stories about Meister and Alchemy. Unfortunately they are designed for a pathos footpocket which I have never seen in my life. Also I have to pay VAT AND shipping ordering form Greece which is more than 80 Euros in total. I can not justify that for a blind purchase!
There are now EXCELLENT Ukrainian/Turkish blades called Deep Master that cost $200. Professional deep divers in Mexico use them and love them. These guys routinely shoot groupers 25+ kilo at depth 30+ meters and they got those fins from the manufacturer. I will try to get them next on my next trip to Ukraine.