I use this 3D printed mount:
https://www.thingiverse.com/thing:4652091
It works great for me, but I’ve heard some reviews that its too much weight for the handy to move a full size fleshlight with the case and all.
In my case I dont go for those crazy scripts where the heatmaps are like solid red, in fact I prefer slower scripts which only occasionally go green lol, so I’m probably an edge case for whom this setup works fine.
I’ve also heard of guys literally cutting part of the case and sleeve off to shorten it, thereby reducing the weight.
Anyway as for longer straps to just strap the sleeve without the case, I think these are commonly reccomended (just not sure what length to get, the one below is just the first I saw):
https://www.amazon.ca/Anti-Slip-Silicone-Multipurpose-Extension-Organization/dp/B0B18BQSF3/ref=sr_1_37?crid=1ZTA1LD6K15A1&keywords=elastic%2Bgrip%2Bstrap&qid=1683167849&sprefix=elastic%2Bgrip%2Bstrap%2Caps%2C91&sr=8-37&th=1
EDIT: oh one extra tip if you go with the 3D mount; I dont print the seperate latch peice. I just use some strong small rubber bands to hold the 2 halves together, its way faster to take on and off than to slide the latch on which is a pretty tight fit.