Nothing wrong with firewall mounted pedals. What is your opposition to a hydraulic slave cylinder? Avoiding the additional work?

No opposition aside from the extra parts. If a clutch cable can be made to work that eliminates the expense of the master cylinder, the slave, and the bracket. If the cable doesn't work, it'll be the hydro.
BUT, if you know of a bracket to mount a slave to a 216 bellhousing, please let me know.