You'll have to check with your local codes about fire wall regs, etc. You'll want to ventilate it really well, such as with a fan or something, otherwise the odors and fumes WILL get into the house. If you are going to work with, and store any flammable liquids, I recommend a flammables storage cabinet, which is designed to safely contain these chemicals, and a good, large fire extinguisher (or two). Industrial suppliers, such as Grainger and MSC carry the cabinets.

There are too many different types and combinations of lamps and ballasts to make a blanket statement like that comparing T5 to T8. T12 is old technology whose time has come to fade away. Older eyes don't tolerate glare well and T5HO in the wrong application will not result in you seeing better. Your ceiling height is too low to be trying to use T5HO and I'm not sure why you'd be interested in T5.

I apologize. It was not intentional. If the duplicate can be removed easily, please do so. I had house guests Tuesday through this morning and was trying to fit in what work and research I could without being impolite to them. I am trying to understand what I might have done. I am confused by the time stamps on this thread. As it stands, my post is stamped "Sat, Nov 26, 11 at 1:47" and your observation that I posted a duplicate post is stamped "Sat, Nov 26, 11 at 10:13. My history shows that I visited the forum last night at 10:47 PM. I had an early morning scheduled and it was already late. I quickly checked the responses I found and decided I would wait until today to say thanks for what I found. I have a project to complete with an early Monday morning deadline, so I will be 'offline' until that is complete. Thanks for your input. baumgrenze

Fixtures with magnetic ballasts that take T12 bulbs aren't even legal in the US anymore (the phase-out got much less public attention and controversy than the current phase-out of incandescent 60/75/100w bulbs since consumers are more familiar and dependent on these). Replacement ballasts and bulbs for existing fixtures remain available. I'd change over to the T8s anyway because they're more efficient, and the electronic ballasts don't hum or flicker. Cold-weather-start ballasts are available, but I've found standard T8 ballasts often work fine in garages even on 20F winter days.