Steve, I have somewhere in my storage LTM peppers catalogue. Personally I went for Pepper 100 and using it with 100, 150 and 200W bulbs.
If you like to have more power then 300/600W combination with GY-9.5 bulb base is very common in lighting for TV/video/movie.
For my location interview kit just for size issue I went with DeSisti, but if I'm doing it again it will be Arri 600.
Using 420W bulbs in open face instrument (EKB; 120V/420W; 3200K;75H average life) never give me long bulb life as it's average life shows.
In my "cheat" bulb lists for Pepper 420 it shows for 120V only 400W and 420W option, all other listed bulbs are for 12/24/30V. Kind of limiting factor.
Fell free to ask me more?
Good luck!