[PeteKz]

Good game plan. I would swap it around a little. Given your rough idle, and that it runs better under load, I more strongly suspect vacuum leaks, so I would focus on that earlier in the troubleshooting tree.

I like to do the easy tests first. I would take off the air filter and look carefully around the air box for any cracks or suspect areas, then I would spray starting fluid around the manifold/head gaskets and the injector sleeves to see if that makes any difference in running at idle. If it does make a difference, then focus on those areas and other vacuum leaks generally.

Since you already have the CIS gauge/vavle, it's easy to hook that up, so that is the second thing I would try. You read the CIS primer and other threads, so you know what do to here.

Be methodical.

Because your car is '77 the Fuel Accumulator almost certainly is leaking, if it hasn't been replaced already. For this reason, I would focus on the FA if the residual pressure is leaking away. Even if it is not the most likely cause of hard cold starting (more typically, it causes hard warm restarts), I think it may contribute to your problems. At any rate, you will need a good FA to test for loss of residual pressure through the Check Valve, WUR, FD, etc. Prove it good, or replace it.

Keep posting your results here.