Hello Ferg,
This will bump up your query for others to add their comments on the motor aspects, I hadn't seen your post before so welcome aboard.
Tablink belting is fine, I see no need to change it but a belt cover would be a good idea. The originals were made from sheet metal with a domed top and ribbing running from front to back, but a fabricated cover in whatever you are happy to work with would be an immediate improvement.
I have a New Progress Number 1 which is a bench mounted drill, the height to the top of the casting onto which a belt cover closes down is 66 inches. With my height at about 5' 6" that is no problem but I suppose your extra 6 inches brings the belt to nearer eye line.
Why not mount it up on packing blocks off the bench to raise it? Crouching to use it will be tiring and unsatisfactory. I do recommend bolting it down though; drill snatch in say 1/2 inch on break through could make these top heavy machines topple over or even try to spin on the bench.
I can't post pictures here, there is some conflict with the process that hides the activate button but if you would like some, send me a PM with your email address.
Kind regards
Brian