HTD belts vs GT2 on Bridgeport

I am about to order timing pulleys and belts for my
BP Series 1 retrofit. I would like to order GT2 belts and
pulleys, but because of the lack of available sizes for
the GT2 belts, I have been forced to look at the HTD.
I have set pulley distances to work with on the machine.
I can easily find an HTD belt to get my pulley centers
within .02". GT2 is not even close. Stock Drive Products
has a poor selection of GT2 belts and I can not locate
anyone else that has a catalog for these belts. I plan
on using an 18 tooth driving a 72 tooth for a 4:1 ratio.

Question: I read that backlash on the HTD belts is a
concern. Has anyone used these belts and had any issues?
Supposedly, the GT2 backlash at smaller diameters is
four times less than that of the HTD.

Thanks,
Scott