Well, if DA says you can dive them in the cave, you can dive them in the cave. I'm not a DIR diver but the Force fins (people use them for wreck diving up here) look like they are designed flutter kicking and direct thrust downward, which isn't always optimal for silty situations. A friend came to Florida for a week of cave diving and after the first dive I hid his Force fins and lent him a pair of blades. He had a much easier time and I "found" the Force ones at the end of the week and gave them back
. The OMS Slipstreams are worth a try if the weight of the Jets is making you fatigued on long dives, they are the same shape and a LOT lighter. They also have the same rubbery feel as the Jets which is nice on slippery boat decks and dive ladders. My feet are about a 10 US and I use the XL for turbo soles and the XXL (which is shaped just like the Turtle fin) for suits with the bigger molded boots.