Looks like they would fall off if there any hard wind. I had some from Stark Bros that had some points in it that made them more stable since they actually dug into the tree a little bit. They stayed pretty much in place unless there was a really big wind storm. Then a few would fall off.
Okay, good that it has some sharp edges. The photo did not seem to show that very well. Yes, get different lengths as Masbustelo suggested. When I got the ones from Stark Bros I bought different lengths. They are plastic.
You always need " another size" when you start putting them on. The ones from Stark were okay. They seemed to do their job. Once the limbs get a certain size or stiffness they are harder to push down or spread.
I hope they do their job for you.
The best to buy are probably treeform V-spreaders. I like simple and easy myself… I havent used them but as far as i can tell they last forever and just do what they are supposed to.
The lathing interests me… not saying its the best but same concept. And more user friendly for stone fruits.
Stretchy bands are also very interesting to me… i think i can pull something easy off with some bungee cords i have laying around.
I got these ideas here… sort of pedantic but i learn that way.