Thanks for your replies. Sounds like I have to wait until the tank fills in a little bit more.
In the mean time I've put in the tank three pieces of plastic pipe - about half an inch in diameter and a couple of inches long. I'm hoping the shrimp - however many are left - will use them as a refuge...

OK, I know that's what cichlids do... I was hoping, since the shrimp were fairly big (for RCS) and the rams are fairly small, that the shrimp would fend for themselves and be able to coexist. Not so. This morning saw one of the rams kill and then eat the largest shrimp in the tank. It was not pretty...