Easy fix, and better than Caps-Ctrl in my opinion: swap Lalt and Lctrl. That way ctrl is under your left thumb, alt under your right. No need for pinkies at all.

You can use software like Kanata to accomplish this if you don't have a programmable keyboard.

CTRL-A seems awkward in that mapping. I still prefer swapping Caps Lock and Left-Ctrl; this gives you similar Ctrl key positioning to the old terminals (VT100, ADM-3A, early PC keyboards) that were used in the early days of emacs and are the reason for all those C- keybindings.