my hotbox is very similar to yours, Fritz, except mine has a hinged door on the top of box. I have 5 bulbs in line on a dimmer, much like yours. I use 25 watt bulbs and have them tented with aluminum foil, like Pat B suggests. I keep a cheapo thermometer in the box, too. seldom do I get it over 90 degrees in there, but It will reach 150 easily if I turn dimmer up to full power. I guess I use my hotbox more for low-humidity storage these days than anything else, but when I need a selfbow stave dry, I'll empty the box of everything but the stave I need dry and turn the heat up.
I think I would work staves to very rough bow dimensions shellac the backs and ends, and leave them to stabilize(read "air dry") for a few weeks someplace indoors(i.e., not outside in the sun or wind. is a bad idea to put really green wood in hotbox, even at low temperature as the danger of checking is highest when wood is wettest. and when you do put them in the hotbox, keep the temp around 70-75 degrees for a week or two and slowly increase temp to 85 or so over a few more weeks. I'm a firm believer in force-drying bow wood, and I've done it non-stop since I started building bows. only drying related disaster I ever had was when I tried to steam an entire stave to make corrections that was too dry. that thing checked beyond any hope of ever being anything but firewood.