FinisFINIS Instinct Sculling Paddle

I swim only freestyle/crawl. I have long used the old Streamliner/freestyle paddles to improve my tech. I got these to also work with the scull motion. It seems to be a constant change in theory whether you should be using your arms as oars or be a propellor. They fit loose in my hand and if my entry is bad, they tend to slip, as named, forcing me to correct my hand position - by instinct when i did it wrong. The only problem is that you can easily scull your hands too far in, across your centerline. Nothing in their design will help that. Incidentally, our locale Y age group coach highly recommends them, He was a 1600 FS swimmer in college.