If you read recurve builds by the masters you'll see that even the most experienced guys will leave the tips wide until they're sure the tiller is correct. That way you can prevent twisting by slightly shifting the tips to one side or the other. 1/2" is pretty narrow for a recurved tip, even if the limb is a normal width like 1.25-1.5".
When I have misalignment of tips on a recurve I typicslly first check that the limbs are properly bending (one side isn't thicker than the other) if it looks good then I know it's misalignment of the tips. I will then use some mild heat bending to try to align the tips properly. This is best done slowly, a little bit at a time. A little goes a long way on recurve alignment. Heat bend a bit to the side you need, then let the bow cool fully, maybe an hour, check alignment, repeat until string is tracking properly. DO NOT TILLER FURTHER AT THIS POINT. The tips may be too dry. Just brace the bow to check alignment. Once yur alignment is on, let the bow rehyrrate for a few days to a week ... The is no such thing as waiting too long, but starting back on tillering too soon is a real concern.
If alignment becomes too difficult to achieve or if you don't have enough stability due to the recurves, you can shorten them an inch at a time until you have enough stability to continue. Go back to heating the tips for alignment as I discussed above after each time shortening.
Moral of the story, go slow at first, never narrow the tips until you absolutely have to (I.e. The bow is nearing completed tiller). A little bit of going slow in the early stages will save a lot of going slow at the end.
I'm sure others with more experience will chime in with their approaches as well.
Again please clarify the limb width so that others can direct their advice most accurately.
