IMHO for light winds 8.5-9.5msails the Delta's are OK as long as you don't put your back foot in the strap but I too find them awkward.
There is really no substitute for length to get a bit of leverage over a wide tail,
I got the longest weed fins I could find 51cm TrueAmes and a Tangent Dynamics (ebay) and just cut them off square at 32cm and makes a great shallow water fin and feels more like a normal fin
You still have to be light on the back foot till you get up to speed tho.
Or make a tri fin like I just did to my old formula board (haven't tried it yet)