Do you mean the original CG-5, or the CG-5 ASGT with the larger, all-metal, tubular-leg tripod?
If it's the former, then I wouldn't recommend it. I've tried it. It will frustrate you.
If you mean the latter, then there are other folks here with direct experience with it.
Normally you use a dovetail. Another method with some mounts is to bolt a plate directly to the DEC head of the mount, then bolt rings to that plate. That method is less likely to work loose, but some mounts' DEC heads aren't pre-drilled for this sort of thing. With cast-metal mounts you might also have a problem of not having enough metal (thickness as well as breadth) to hold bolts and/or anchors securely.
If you use lock screws or clamps on a dovetail, it should perform well without slipping.
I don't like the Vixen-style dovetail bars that Celestron uses because they're lightweight and narrow. This makes them more susceptible to flexure. You don't want flexure in a photographic setup. However, many folks have used this system for decades and have produced good results ... so, as long as you don't overload it, you could be okay.