Yes, it is the Delfins I have (...) By the way, anyone know where I can buy another pair of them? I guess I would get a small improvement with a new pair.
Other than Russian online retailers, I know two reliable sources of Alphaplastic Del'fins, both of which I have used in the past:
1.
Triton Underwater Swimming Equipment
Triton Underwater Sport Equipment
Based in Ukraine.
2.
Schwimmen-shop.de
Schwimm Shop für FlossenSchwimmen Rettungsschwimmen Triathlon Wasserball Orientierungstauchen Unterwasserugby - Russische Gummiflossen "Delphin" neu GF 02
Based in Germany. Don't select "offener Hacken" unless you want to pay more for a pair with the base of the heels removed!
They are great for all day everyday, but I want to find an improvement in speed and some free recoil. I have mine trimmed off to the first rib to more better simulate a mono fin.
If you're based in the original Taunton in the English county of Somerset and not in one of its namesakes in Massachusetts, New York or Minnesota, you have several all-rubber full-foot fin sources. I have no idea whether any of these products, all available from British online retailers, fulfil your criteria of "an improvement in speed and some free recoil". All I know is that they have stiffer blades than the Del'fin has.
1.
Majorca Dolphin
Eyeline Swim Fins Senior for £11.23 at Newitts.com
Inexpensive, soft rubber fins, very comfortable during extended use.
2.
Sub Gear Jelly Fins
Sub Gear Jelly Fin | Snorkelling Fins | Simply Snorkel UK
Flexible-bladed Taiwan-manufactured fin with very soft heel.
3.
Win rubber fins
Rubber Fins --- Bishop Sports & Leisure Ltd - Home for Sports and Leisure equipment to Schools and Collages
Malaysian-made fins, rather narrow fitting and and with variable stiffness.
If you're prepared to look further afield, many all-rubber full-foot fins are still manufactured around the world. I'm particularly fond of the Mexican-made
Escualo Clasica, which has a broad-fitting, very soft foot pocket:
and the Japanese-made
Gull Mew, which comes in a range of solid colours and is a popular choice throughout the Far East:
I'll leave it there for the moment. I can't vouch that these fins meet your requirements, not least that they will be good fit, but I've tried them all and I'm happy to swim all day with them. What suits me may not suit you, though.