Just from my experience...At my Home Depot...
That being said...I just recalled, the same friend told me he found a 300w eq self ballasted in a grocery store (he lives in KC) and it has a medium base and he is currently using it (I believe) to winter some tree indoors with a high ceiling.
I believe this is a 65watter, like mine in the pics, but in the user friendly medium base and self ballast. I assume your local hardware has these? HD and Lowes in SD do not.
Hope that cleared up the confusion...If you can find the >42w bulbs I would try them as long as the price is >~$15 USD. If not smaller bulbs with splitters (Y adapters, use two to make 3 sockets) are more economical.

