Building up a 1970's frame

A bit of background. I've got too old for my sport (rugby), and hope cycling will keep me engaged for many years. I do about 1200 miles per summer on a road bike, and want to build a fixed gear bike as a hobby for winter riding - not least because I really want to build a pair of wheels without duplicating what I've already got.

I bought a Puch Cavalier frame with horizontal dropouts. It is complete with forks, but otherwise naked. I'm looking for advice on the componentry. With this frame, nothing at silly prices, but I don't want it to be rubbish either. I'm thinking: Miche flipflop hubs, a tri-style handlebar and (because the BB is fairly low) relatively short cranks. I'm confused about the BB: I'll go for a sealed unit instead of replacing the old cup & axle that would have been original, but should I stick with internal bearings, or try to fit externals (I'm not interested in having the ends milled down)? I think Truvative GXP units may be able to function well without having the BB ends faced?

Similarly, headsets have moved on a lot since this frame was made. I'm assuming that an Aheadset would not fit the head tube/fork combo. If correct, then what is a good modern threaded headset?

All help greatly appreciated.

On the saving money part, I used some really good grease and new bearing and rebuilt the original headset and bb. 1" headsets do need a fair bit of adjustment so just keep on top of it :).

Cranks on old bikes seem to go from very small to very large, 165 to 180mm. Mines got 165's, seem good for my gear ratio (70gi ish)

Dixie, Sheldon pretty much covers everything bike related, (if you have not already found him) also the Peugoet thread here has some useful general info

I think a lot of people don't recommend Miche hubs as they have Italian threading that is not common.

You can fit an aheadset to threaded forks, but 1" threadless headsets are unusual and tend to be expensive. Get a stronglight threaded headset. Awesome. Tange are fine too.

BB just buy a Veloce or Shimano UN54 basic one, dep on what cranks you have.

Tri bars sounds wack on an old frame, but hey it's your boat, do what you like to make it float.

on one hubs are about £30-40 for the pair and have good enough sealed bearings.