I've tested PVS-30, PVS-27, Oasys, C35 on:
KRG Bravo w/ KRG's accessory NV fore end
Desert Tech SRS M2
Accuracy International AT w/ Cadex NV bridge
Sako TRG-22
All worked with 1.5" rings. With 1.25" rings there were problems with Thermals that affected usability. With NV problems weren't nearly as severe even without the beer coozy dealies in place.
One piece/continuous rails have not been an issue even with up to 30MOA of scope cant relative to the rail provided 1.5" rings are used. 1" rings caused quite a few usability issues. I also ran into problems of limited NV rail space to get PVS-27/30 mounted on TRG-22 with longish overall length of the day optic. Others were not a problem with the optics I tested with (IOR Recon, Steiner M7 4-28x, Crimson Trace Series 5 3-18x, SWFA SS 10x, NF NXS). If you're not blocked from going to a dedicated rifle for night shooting you really open yourself up as far as less expensive options. Clip-on is the route I went simply because I wanted 1 rifle for everything which had effects in terms of increased cost for the night vision/thermal devices, increased weight, increased complexity and scope length concerns. YMMV.