I really like the split open tennis ball idea. The ball is lightweight, but having that slit can allow for added weight. The only problem I see with that is bounce back.
I just mentioned in the cam strap storage post that I’m an arborist. So, with that comes throwing throwballs everyday. I should mention that I don’t climb trees with spikes/spurs/logging cleats unless I’m taking a tree down for good. I’m setting my climbing line from the ground and ascending up the rope and branches.
You get a lot of practice with aiming for branches. Branch unions. Hangers. Etc. don’t get me wrong, there’s plenty of days where you’re constantly throwing and missing, getting your throw line knitted up, or caught, or broken. You get semi good at hitting tour mark though.
Check out some arborist suppliers or tree work suppliers
sherriltree
tree stuff
bartlet
weaver
i use the thin 1.5mm - 1.7mm line with an 8 oz weight (12oz for work). The line is strong as can be, high viz, can get upwards to 1,000 feet. Its smaller than paracord, just as strong and stronger (Dyneema or spectra), and it floats if it falls in. The weight is optional, I can handle an additional 8oz hacky sack.
hopefully this helps somebody out
chexk out some other tree climbing gear, micro pulleys. Swivel pulleys. Carabiner pulley combos. Create 3 to 1, 5 to 1 for the WFA’s.
I also keep a 2 DMM xsre carabiners in my gear, they’re 4kn (900lbs). Worth getting!!