Pebbles had the same problem. She actually got a pretty bad burn on her right leg during a trip from the extended saddle time. Do a search for half chaps, there's both motorcycle specific ones and equestrian ones. We visited a couple tack shops and its was amazing how many options were available. Some shops even had used chaps- high quality gear at reduced cost.
Pebbles was able to try on several brands and sizes before finding a good fit. Hers have a solid leather front wrap around and the back has elastic leather. They zip up on the inside of your legs and once on just look like tall boots. They have taken care of most of the problem for her. Full chaps was just not a style option for her. Note- they came with an elastic strap that went under the boot. They were also a PITA to get into place and zip up. After a couple of months of use one side got frayed and came off. Turned out they weren't needed and she cut the other side off. The chaps stay in place and don't ride up and can't fall off. She gets compliments from other riders on how good they look. She wears the over the ankle style boot and the half chaps fit over them without a problem. (Ok- so there is some grunting in getting them zipped)
Pebbles mainly had heat problems with just the lower right side. If you still have a hot seat issue you could look at beadrider seat covers. I use that on the ST1300, which is a really hot running bike. During the summer I also stick an Airhawk seat cushion under the bead rider.
Funny story on finding a solution for Pebbles' burning leg problem: we looked at pipe wraps, alternative cooling fluids and even physical heat shields like you say you're working on. Full chaps or heavy riding pants weren't an option. I tried wrapping her legs in a pair of welding gloves then hit on the idea of using one of the those heat resistant silicone kitchen mitts from Bed, Bath and Beyond. It was very thin and had thick stitching that I cut to thread a nylon strap through. The worst of the heat was just on her lower right side and that's all she really needed relief for. While riding it wasn't visible except for the two straps holding it in place. When she got off the bike she took it off with two quick clips. But sometimes she would leave it on and told people that asked about it that it was either a gun or knife holster. That actually got her a little respect in some groups
She rode with her kitchen mitt on for about 4 months before we stumbled across the half chaps. It's funny more dealers and leather shops don't carry them.
Good luck finding what works for you!
Terran Sin
Amateur Leather Lorimer for Pebbles