This is the final re-constructed message of this topic posted by the ANZLF help team.
downwards force on a conventional DB bridge is around 15-20% of the longitudinal tension. so that's 60lbs each string, with a total downwards force of say 50lbs (all four strings). this will change if the string angles over the bridge are different, and different brands and sizes have different tensions in the first place.
But I don't know how you're going to use that info.
The acoustic volume you get is related to the size of the vibrating top and body cavity ... even on a double bass this is barely enough!
In my opinion the acoustic timbre of the Double Bass is due more than anything to the damping characteristics of a large sprung top, which is very hard to reproduce in a solid or chambered instrument. And you likely won't reproduce it with magnetic pickups, only piezo elements or microphones, and then only if the timbre is right in the first place.
A lot of the sound result depends on the technique of the player, too; the left hand technique is very important in getting good sound.
I think your best bet for sound would be a small bodied bass with as large a top area as possible. Build it as light as you possibly can without it collapsing, but maximise the downwards force on the top to get it moving and damping the sustain. Laminate sides and back for strength. Stiff neck and conventional fingerboard, 40" scale. For arco playing, the soundpost+ bassbar design has kind of proven itself over hundreds of years and contributes to the acoustic bass sound. passive piezo pickups in bridge, a good preamp.
simple isn't it?
