Cant go wrong with a 5.0/6% T5 HO. Its only the 10.0/12% you have to worry about.
A 5.0/6%, without screen, will provide uvb for about 2.5ft into the cage, by then it will be a UVI of around .5. And as beman pointed out, you want the max closeness to be around a foot a way, that will put you around 2-3 UVI. If it was an all screen top, the screen would filter maybe 1/3 of the uvb out, so you could get closer, around 6-7". So yea pick out a zoomed 5.0 or arcadia 6%, get it long enough to run the length of the top, and angle the basking stick so its a foot away from the bulb and tapers down to 2ft away.
I wouldnt bother putting window screen across the top to try to mimic "screen"cage. I have my fixtures in the cage with nothing blocking the bulbs what so ever, I just set it up so the stick is at an angle so they can tune the UVB as they please. Same with the basking light, you want a gradient.
You also mentioned a basking light. I lean towards halogen wide floods, but can not guess what wattage you need. I run 2 35 watters pointing straight down so have a 1 foot long warming area. For all i know a 65 watt at a 45 degree angle would be perfect for you.