cant hook up Et street radials help???

What do you mean you can't hook up? What kind of 60' times are you getting? What is your launch style? Drag radials work great, but you still have to be a little gentle on the launch. You can't just dump the clutch and expect everything to happen.
You shouldn't need a tube and at your power levels, you shouldn't be anywhere near needing screws. In fact, I'm pretty sure you shouldn't and shouldn't need to screw a radial tire.

I have ET streets and just mounted them on the wheel. no tube, no screws. I had a similar question about a month ago on here and got some real good advice. you don't need to get them real hot(you can over heat) run them around 15psi but you can go as low as 12psi. now this is for the ET streets not the drag radials
check out the thread below
http://forums.stangnet.com/781000-what-am-i-doing-wrong.html

If you can slip the clutch enough to pull away from a stop light without a Nascar style start, then you can slip it on the launch at the track. Side stepping the clutch is just mindless and gives you no control at all.

You just need practice on hitting the engagement point on the clutch just right. Bring the rpms up to a steady 3500 and slowly let the clutch out. When you feel the car just barely start to creep forward, push the clutch in just a hair so you don't creep forward. Then, give it much more gas and draw the clutch out an inch or 2 without letting it fully out. This will help you find the engagement point where the clutch needs to be on launch. I do that method everytime at the track, but be aware that sitting at the line with the clutch partially out will start heating the clutch up, so don't do that for too long (my clutch has gone 70k miles and at least 30 passes at the track this way).

As for launching on the nitrous... try launching this way without the bottle first. You will generally be at part throttle while slipping the clutch and then got WOT after the clutch is engaged. This method would then transfer well when you hook up the bottle again. Launch without the nitrous, then when the clutch is engaged, put the petal to the floor to start spraying.

The torque of the spray is breaking your tires loose. I'd try to spray in second gear after you launch hard. Once you get that sixty foot, down, your ET's will drop even though your spraying in 2-4 gears. Launching a 2v with gears and spray is tricky. Much harder than a blower, or turbo setup. I would skip the ET streets and just go to the ET drags.

what type of suspension set up are you running?

My ET street radials were sticky enough to snap my drivers side axle at the track last night. I was only launching around 3500 rpm too. To be honest, I think it snapped when I shifted into 2nd gear. Time to move on to a 31 spline setup.

edit: I would stay with the 26" tire. If you had 4.10's I would have suggested the 28" tire though.