Thanks for the replies. I appreciate the input. One of my flying buddies gave me the answer to my output splines question. The Tower TS-63 is a private label Hitec, so the arms it uses are Hitec-compatible.
Rafael, Yes, in some ways I would qualify as "old school"--especially because I'm building a design from (gulp) 42 years ago....and I take that as intended--with a wink and a smile!

Kevin