Arthur, how did I miss your thread? Nice cab, plants and strains. I like the CFLs, I bet two will really rock!
I noticed you were having temp issues. I assume you flower at night or the coolest part of the 24 hour period?
Fans blowing on your bulbs would cool the hot spot as well as mix cooler air in the cab, netting a lower temp ceiling. If not blowing directly on the bulb, set them up to blow between the bulb and canopy. Plants will benefit from the air circulation and temp reduction. The bulbs obviously warm most of the upper cab but there's an even hotter envelope around the circumference of the bulbs. This "hot spot" is what fans would help dissipate.
I hate to mention after you've completed your cabinet. Active intake is possibly cooler than passive intake but it's much harder to tune air-flow. For this reason, your exhaust fans may endure more static pressure from the intake fan as opposed to an open hole(s).
I'm not attempting to get you to change your setup. But IMO, if you're having trouble with the temps, passive intake(s) will work better.
To overcome typical pressures in the cab, passive intake needs to be 2x the size of each exhaust fan. I'd make both your large fans exhaust and cut three more intake holes the same size as the original. You could instead cut one square or rectangular hole 2x the area of the combined exhaust. That should get you within 4 to 6 degrees C above ambient, maybe cooler.
The hottest months will be tough but high heat strains may do just fine if flowered at night.
