I'm with Doug. Well, not physically. I'm in CA, he's in AZ, which are touching, but I want to say right now, I've never touched Doug with anything other than my words, and he me with his.
As a Dad m'self, I commend you on your research skills that led you this forum. The most helpful people on the web are right here. You will get more bang for the buck used, and there are many posters that will offer opinions on specific speakers you may find, say, on eBay.
Does your Dad like to mess around with things like audio, or is he more of a "set it and forget it" kind of guy? Part of the fun of vintage speakers is finding out about their history, and talking (here) with others who have them (not that the current line-up doesn't get a lot of air time on the boards).
Good luck, and keep us informed!
fini