Want brightness ?
Go to your local electrical wholesaler(s) and ask him for a 2-40 (4'-2F40 lamps) industrial fixture
or for a 2-96 (8'-2F96 lamps) industrial fixture. You can combine 4 of one of the models or 2(4') and 2(8') of the other.
The fluorescent "industrial" fixture that you purchase at an electrical wholesaler (especially the 4 footers) are very different than the ones that you purchase at a hardware store /home center (Ace,Lowes,Home Depot). Why, the 4' "Shop lite" as is known in the in the consumer market, uses a "low-light-output" residential type ballast, why ? (Cheaper), the one that you purchase at an electrical supply house uses an energy saving ballast that is a "full-light-output" that works at say, 100% efficiency (more lumens) the residential grade ballast works at 75% efficiency, less lumens. In laymans terms, one will generate 34W (ESB) the other one 26W (residential).
Even better than the above, try to buy something that has an
electronic ballast that uses electronic or "octron" lamps, ex. F32T8TL741. These fixtures will cost you more (because of the ballast and lamps), but electrical consumption savings will be approx 40% better than the magnetic (T12) fixtures.
Electronic is the latest technology in the fluorescent industry and it is much more efficient than the old magnetic technology.
The term "industrial" is given to a fluorescent "strip" or "channel" fixture, in which they put a white shade or reflector (as you would find in a shop-lite, usually with a better quality steel in the reflector/shade), which helps to direct the light downward.
What would I use in your situation ?
Go to your wholesaler and as him for price and availability on:
1) A fluorescent electronic strip for a 2 lamp 4' with a chrome reflector 120V (I presume you have 120V)( the chrome reflector will duplicate the "lumens" over the "industrial" or white reflector/shade) that includes lamps (octron/electronic 2-F32T8TL741).
2) A fluorescent electronic strip for a 2 lamp 8' with a chrome reflector 120V (I pressume you have 120V)( the chrome reflector will duplicate the "lumens" over the "industrial" or white reflector/shade) that includes lamps (octron/electronic 2-F96T8TL741).
Price both sizes, with and without the lamps, and see if you can purchase electronic T8 lamps cheaper some place else. Use ONLY american lamps, GE, Phillips, Sylvania. Do NOT use imported electronic lamps (they suck), I recommend Phillips "Alto"they have the green colored ends (enviromentally friendly) but GE or Sylvania will do, only recycling is recommended for those two versus disposing in you garbage for the (Phillips) Alto's".
I suspect the ones with the chome shades will have a bad availability, if so, and you need them faster go with the industrials.
Common part numbers for the above in the industry: CI232 (4'), CI296T8 (8'),
IND232 and IND296T8
EJ232, EJ296T8 (Lithonia)
Just my 3.8's...
