Recently had to adjust an prewar calfskin topped 5 string when the danged bridge would slide about. I found that contrary to common misinformation, a higher tension does make a lot of difference in these type instruments; but not in the copies which were NOT made for gut string like the originals. So when the bridge is deflecting more than 1/32nd ,too loose, need tightening, tricky since the other way - I have not managed to get there yet - it should begin to crack the top.

I do notice that in the prewar models, and I have sought out several, a real hide top and no 'padding' in back sounds very early Scruggs like!; to the Seeger style player inserting a good quality sponge into the back - under the tone bar - will make a very nice sound.

But if you want to be in the dweepickums today, playing early BG and OT seems to be the way to go. I can't do either that well but I love the sound!