Well, I didn't wait till winter to install the second light............. Bought a fixture and bulbs and replaced the one to the left in the pics above in post #39. They (both fixtures, all 8 bulbs) use 4.0 amps on 120v and this is the exact same draw as
one of my 400 watt MH lamps I installed in '08 (has it really been THAT long?). They put out enough light that for all except detail work, I can have both workbench lights on and I can turn on just the middle row of MH lights in the shop and have enough light to work with. Someday, when I'm rich, I'll swap the MH lamps for 8 bulb T5HO fixtures with wide spread lighting and lots of uplight.
Anyhow, walking by the lights this evening, I wondered........... HOW HOT? so I grabbed a step stool and reached up and put my hand on one.........
I quickly felt like the village idiot as he picked up the horse shoe just out of the blacksmiths forge and flung it up in the air........ "horseshoe was hot wasn't it?" asked the blacksmith....... "no, it just don't take me long to look at a horse shoe" replied the village idiot.
Anyhow, It was about 60F in the shop this evening, cooled off quickly when the sun went down, as the shop was opened both ends and the ceiling fans running till way too late. I got out my multimeter with built in IR non-contact temp and held close to the bulb (it gets a 1" spot at 8") the meter read 157F. I used the Alumel/Chromel type K probe and plugged it in and it showed mid 30's temp so I have to assume it is off by 25-30 degrees. I clipped it to the bulb with a plastic alligator clip and after a few minutes it had settled at 127F, which if you correct for how low it was reading, is real close to the IR reading.
I think that any concern about these lamps getting below their optimum operating temperature in a cool, or even a cold shop, it "much ado about nothing" as Shakespeare would say.
Charles