Okay; I pulled my "ABG'd" 1/4-sized Englehardt out of the corner to refresh my memory before responding to this thread, and the final verdict is: if one wants something like an Arco Bass but for whatever reason cannot obtain one, then IMHO a quarter-sized URB is the way to go. It comes closest to the Grail everyone seems to want: an acoustic bass guitar that plays as easily as a Fender but has the tone and volume of a double bass.
Vertically, it can be bowed either standing (with a beastly long endpin) or sitting. Standing, it can be plucked with the aid of that same beastly long endpin; standing, hung from strap, presents ergonomic obstacles -- mostly caused by the combined weight of the scroll plus the tuners -- I have not yet found a solution for. Ah, but SEATED and played upon the lap, it is that Grail experience.
The only discomfort comes from the tendency of the edge of the rear C-bout to dig into the thigh -- easily remedied by placing a folded towel or small cushion on the thigh. The nut is easily within reach. With the forearm resting across the upper C-bout a natural srrikepoint is created, with the thumb placed against the very end of the fingerboard for leverage. Volume is not as loud as a three-quarter URB, but IMO is plenty loud for coffee shop playing -- which is the performance venue most want to use ABGs for. And the URB tone is here in spades. I have used mine to back two singer-guitarists, both of whom were miked and were playing amplified acoustics. My little Englehardt had NO onboard amplification. I just sat between the singers, about six feet behind, and bled into their vocal mikes; and I could be heard just fine.
My Englehardt EM-3 is almost completely stock, the only modification being that I used aircraft cble to make some tailpiece extensions so I could include electric bass strings among my string options. Right now it's loaded with LaBella tapewounds like one can get through the Carvin catalog, and the "mwah" factor is off the scale. My little plybass
I got for under $300 I would say sounds as good as basses costing ten times as much.