Most of the RJ/Bickel/high end guys will all slip fit their stuff and plug weld it from the side, whether it be wheelie bars, wishbones, etc. We had two sets of McAmis bars laying around in the shop, one off a rail car, the other for a Top Sportsman car. Nothing special with either of them, but I wasn't terribly keen on the wheels they use on them compared to the ones RJ offers.
I will agree with Todd in that I think how hard the car hits the tire is more of the deciding factor than length, especially with the stock suspension stuff, and even moreso with the drag radials. From what I've seen, the drag radials can be so finnicky on a marginal track, that the best results I've seen were as Todd mentioned - set the bars high enough to keep from going over, not so much as to control the launch. This lets everything work as it should, lets that front end have the slow, controlled rise, and should keep from unloading them.
On the other hand, if you've got a nitrous car leaving on a 10.5w, that front end is going to come up hard and fast, and is probably going to unload once those bars hit the ground.
As a side note, most of our customers running super gas/super street with big tires all run short, unsprung bars to basically keep from seeing the roof, and the slowest of the bunch are in the low 1.30 60 foots.