El Gordo.... you want enough belt length to accommodate anticipated wear, which adds length to include over the hips and over winter long handles and woolies. Might also anticipate a little broadening of the beam with age. Especially with a buscadero-type with separate, narrower-than-belt tongue, the tongue should be long enough for hitching summer and winter.
David Bradshaw
If you get the type that has that extra piece of leather for the strap that go`s through the buckle you can have a shoe repair shop move it out longer. I did several times but have run out of adjustment long ago. This is a rig I had Alphonso of Hollywood build me back in 1971 for my colt 2 1/2" python. I believe his son makes them now.
http://www.alfonsosgunleather.com/