I'm using that gimbal lock and I love it. It's made of a semi-rigid rubber and once you flex it around a bit it's easy to install. I'd recommend watching the install video if you haven't already. I don't force the lens into the cup, just casually press it in a bit and it holds just fine. I specifically ordered it for use with the Taco RC ND filters, which I leave in place all the time. I think if the cup were just a bit bigger/wider, the lens would slip fully into place, but I don't see enough movement in the gimbal or it to be an issue. I did run my finger around the rim of the cup to loosen the material up a bit, so maybe that's why it fits better? Anyway, I like it...it's red, sits right in front so I can't miss it, and does what I want it to do!