Good glass is not much good if it is not carefully matched, positioned, aligned, securely mounted, baffled etc etc. Good lenses are just one of many things you need to get a good eyepiece. How you can get the precise combination of lenses you would need for any half decent design from "surplus" is beyond me.
On the other hand, he's even got stuff for
"imagery applications", so he must know what he's doing.
