Re: T8 or T12
I agree, T8 is the better choice. In my experience, they give more light. Make sure the ballast is compatible with T8; both T12 and T8 use the same sockets but usually they are not interchangeable.
One thing that will be important to you is to select the right "color" -- it's measured in Kelvin and comes in values like 2700, 3500, 4100, etc. The smaller the Kelvin value, the pinker the light; the larger numbers are bluer. 3500 is roughly equivalent to "soft white" incandescent bulbs, but I think 4100 gives a more natural color.
The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.