750-800 media temps is not too hot for the brass. Keep in mind, this is merely the temp of the media- not the temp the brass will get to. We are, afterall, predominantly comparing this to a 3000F +- propane flame.
I really doubt being particularly accurate on the pot temps matters much. Why? Because the dwell time is going to be the important factor, and the media acts as a thermal bank to smooth out irregularities in temperature. Hotter media? Shorter dwell time. Heat through the media? Convection will move the heat via airflow in addition to conduction and even radiation (IR). Brass should only be dipped in about 1/4" and will be towards the center to avoid burnt fingers and irregular heat. Were I to guess, the minimal convection pattern pulls air through the center of the media since the perimeter is the location of highest heat around the much more conductive pot. In practice? These issues *seem* to not matter much. But I will eventually have some better answers.
Protection? I will tell you that hot sand or bead media is nowhere *near* as scary as molten materials. Glass isn't particularly conductive, won't stick to most protective gear, and can be brushed off. You could dump it on your cotton jeans and still make babies after doing a little dance, but you would NOT want a grain in your eyeball! I wore gloves at first but then quickly decided it was not necessary- though I did routinely burn a finger here and there. Not on the media though- it was the pot that would get me. Molten mediums can be pretty spectacular if they contact liquid too.
But the media is more than hot enough to ignite flammable materials like powder or lead styphnate. I'd absolutely keep this process where it cannot tip over anywhere near powder or primers.
Of course be especially wary of synthetic materials- like polyester pants for instance. Glass would *immediately* stick and melt the polyester which then would stick and burn the smokes out of things you'd rather not. Cotton? Might singe after a while, but brushes right off. A non synthetic whisk broom and metal dustpan might be a good idea. Tighty whities under the button fly is probably in order as well. Apron? Maybe so. If it managed to pour into a front pocket it would also be no fun!
But let me explain why I make some of these points: In my minimal experience playing with this process, it *appears* to not only be extremely forgiving, but also cheap and very fast. If a cheapo $35 Lee pot works, then this process is opened up to pretty much anybody who is willing to learn.
Give it a try and post some results. I have the gauge on order from Taiwan, so you guys have a month to beat me to it!