Proper Gauges for Nylgut strings 4 Frailing on Vega.

Hi pluckers and frailers,
need your wisdom for the better type of strings to play `Old time music and fiddle tunes` with nylgut strings on my Vega.Should one be looking for light,medium or heavy gauge strings.Or would medium light GHS be the way to go.Can someone suggest a proper set (brand and gauges)for me, or two or three to try, that would suit the music that appeals.

Tani Frailer, once Tani Plucker....lol

p.s Can someone also suggest the best device for measuring string gauge and where to purchase on.

Many Thanks K.B.