Help using eval in screenrc

I recently asked how one can stack commands with one keybinding in screenrc

One poster pointed me to eval, which is surely the solution.  Much googling for examples confirmed it can work.

But alas I have had no joy trying to modify the examples for my purpose with multiple trial and errow attempts.
I want to do a keybinding with eval to stack these commands which work now when entered manually:

1. enter the command c-a, defined for me as ^F.  I couldn't find in the examples if this a literal ^F or some
other representation of the command key.

2. do a "hardcopy entering h, one example suggests a -X hardcopy works, no joy. wen tried.

3.. Enter an already defined keybind with exec which runs a shell script manipulating the hardcopy text file.
-- 
Has anyone experience/suggestions for this?

Many thanks.

Dan
XB