I cut a slot in mine because I stripped the phillips head about the 20th time I took the carbs off ;D
Now I just use a really long flat blade screwdriver.
I only loosen the clamps that hold the carbs onto the intake. I dont take the boots that go to air box off. If you tug on air box it will come off ok, then just put a little oil (usually some in air box) on the boot lips before you try to put it back on... takes a little practice but gets pretty quick. You will have to take filter out and work the lips back onto the box when you put it back on. Still easier IMO. Have done this many many times to several different SV... works fine and no damage.
I was thinking that with an allen screw and a ball driver you can get to the head and not have to be inline with the screw to make a good engagement if that makes sense. Easier to take on and off for sure and you can always be sure that you get it good and snug. It looks like it might be a 3.5 x0.6 mm or 3x0.5mm screw.