k10

Cool good to hear he loves it. On the velcro note as suggested above I've had a few gloves with single D loop and hook n loop straps that work great one handed, to the point I've tightened or removed one with my teeth easy enough when holding something I couldn't let go of with other hand. Some brands (eg. velcro) can be harder to release than other brands so it is good if can see it in person or get accurate review first (although strong hold may be preferable of course).

as far as water resistant finishes go I only use resolene really. I don't like it neat so I thin it down but I suspect it affects the water resistance doing that, you'll loose some I imagine but get a more satin less acrylic looking finish plus I can get it through my airbrush and do several coats instead that way too. As mentioned laquer and a few other finishes are possible too. I've heard of some even using clothing waterproofers or heavy workboot proofers with mixed success and high degrees of resistance in various finishes from gloss to matte. If accidents do happen and it absorbs some water if you leave it to dry naturally and don't stick it on a radiator or near the fire or something I've found a lot of stuff isn't ruined and will survive fine but better to avoid obviously and sometimes it will mark or cause raised waterspots. On the note of heat I imagine cold drink use is fine, for hot liquids though I'm not sure how they stand up to use over time as if it gets wet in that state it will easily swell and warp a lot and it'll dry rock hard and a lot of finishes may not be heat resistant too. Whatever finish you settle on I'd still air on the side of caution and make a several scraps up to test them first so you know how it'll be likely to act in event of incident.

You do the tooling wet too. I generally do it at the same time as swivel cutting. Damp it well and wait for it to lighten in shade and start cutting them stamping. Too wet and it'll be spongy and not take an impression well and mush details, too dry and you wont get deep impression and cuts drag. For stuff where I need to wetform it too it may take a dry step if I form after tooling; I do some after tooling and some before depends on various factors but if I form it after stamping without a drying step it tends to affect the impression depth where if I dry it after tooling then form (esp soaking from the flesh side rather than skin side) I have no problem. This is just my way and I'm far from expert so ymmv and others may have better way but you'll generally always tool wet/damp.

For flexible I like renia ortec and use it in shoe/boot contruction as only thing I find sticks vibram without failing over distance/time but I use on leather to leather bonding too from watchstraps to wallet linings. Leather to leather is overkill I suppose and more expensive than PU contacts like barge but I use it because it is what I have the most and I like it because it is stronger and doesn't foam like some modified neoprenes do. For less flexible stuff I like GFlex and for stiff gluejoints any polyamine/amine epoxy over 3.5 ton psi because it is strong and bonds leather to almost anything if done properly.

If you can get it poron for prosthetics and orthopaedics is what I prefer to neoprene as it is designed to absorb shock in such applications and it doesn't compress over time as easy. I find it breathes a little better too where as neoprene gets sweaty I find. If you're using glue to bind layers as well as edge stitching then Ortec is the best for sticking it I find, I usually prime it with their PUR primer but ymmv without priming. There are different colours for different force spreading, impact resistance and cushioning. The red tends to be more comfort surface than impact resisting as it is very squishy, best bet if you can get it is check their charts for most suited to your needs or a similar poron equivalent maybe (I use the medium densities the most and buy in rolls but many places sell small pieces). Pity not in the UK or I'd send you some as I could post it cheap within the country. Just my opinion and maybe not what you'd want but I guessed it was for abrasion protection from pushing the chair rather than full on wrist support. If it is just palm protection being overly thick maybe uncomfortable depending on the user. If it were me (wearing I mean, not making) I'd use as thin a stock as possible like 1mm vegtan goat or something very supple and add thicker kagaroo or bovine on the abrasion prone point. Maybe a thin layer or cushioning (neoprene, poron etc whatever you can get) on points likely to cause issues if left unpadded. Apologies if I've missed the point and it is for wrist support, I'm thinking along lines of what most I know use them for which is palm protection when they travel around a lot and most don't have full chair handles so they do it all under own steam which is heavy on the palms at times.