Hi Will, There are templates of the Ventures I model on eBay pretty often and they cost $50 or $60 if you want to go that route. I'm not sure how accurate they are, Having never purchased a set but I have a Ventures II (Of the later model) That I'm restoring. I don't know how close the neck is compared to a Ventures I model but here are some measurements of my Ventures II neck and frets, in thousandths of an inch.
The frets:
.070 wide, .022 or .020 tall on the bass side tapering to .015 on the treble side. Frets that are .070 wide aren't made now to my knowledge but Dunlop has a set that's .072 wide and .035 tall so if you want the frets to be vintage spec, Using these frets and filing them down is as close as you can get.
http://www.shopamw.com/servlet/the-4020 ... LAT/DetailThe neck:
Width of neck halfway between zero fret and first fret: 1.541 (Its 1.553 at the zero fret and behind that at the string guide there's a slight taper to the headstock)
Neck thickness from back of neck to top of fretboard: 845 or .850 except at and near volute and neck heel where there are tapers
Fretboard radius: 10" or so
Fretboard to volute thickness, Between zero fret and string guide: 1.380
Fretboard to neck heel thickness at 16th fret: 1.125 (The heel has an angle to it too)
Also, There's a bevel on the sides of the neck and the frets are extremely low in this bevel. This might only be on the cheaper models like mine and I think it was a way Mosrite avoided rounding the fret ends.
Austin