I think you got it.
Luminance : candela/square foot
Illumination : foot-candle
So the old Weston meters do show candela/square foot. You really need a convenient way to get candela/square foot to really enjoy the Ansel Adams Exposure Formula. Old Weston meters would be a way to go.
The L-758C can't be programmed to display candela/square foot. It can display foot-lamberts, but then you would have to convert to candela/square foot which would take some of the fun out of it.