Ann, with the SOLAS tape, I've had some luck using Contact Cement to glue it onto foulies that didn't come with the stuff already in place. And I'd reckon that there are other adhesives that would work
also. Plus, said tape is integral to many construction safety
vests, which are cheap
enough to cut up & sew onto your dinghy chaps, assuming that the fabric
will handle the UV that is.
They also make similar (reflective) tape for use on motorcycles, & bicycles. I've put it on bike rims & my helmet, & it had little trouble with the elements even on bikes I used to commute to work
year round. And the rims spend a good bit of time in the wet, as does the bike.
The perk is, since it's not "marine", it tends to be cheaper.
One other option is to weave some small diameter cord that comes with built in reflective material into the lines which run around the perimeter of the dink, & that are used as hand holds. Or even serve sections of the dinghy handles & grab ropes with the stuff.
Usually you can find it at outdoor gear
& sporting retailers, along with large cordage outlets. I discovered it one day when looking at tents, where it's used as their guy lines. So that you can find the tent at night, & also don't trip over said lines.