I wanted and finally got an answer to my original question. Thanks!, by the way.
My interest is to make a Handi-Rifle as versatile as possible - usually. "Usually" most often depends on whatever crazy idea I might be considering at a particular moment, but also staying within a practical budget.
The Versa-Pak .22LR barrels are off-set so the firing pin on an SB1 (or SB2) strikes the .22LR on its rim, not in the middle that would do no good! The Sportster (rimfire receiver) has an offset firing pin for those [Sportster] barrels.
When shopping on eBay one needs to use a little intelligence about costs, prices, shipping, postage, etc. But many e-"buyers" obviously get carried away bidding online or trying to out-bid one another. Whatever.
If I could pick up a .22LR Versa-Pak barrel to have to add to my Survivor's capability and versatility, I'd be willing to pay up to $75 to get one and have it fitted (not by NEF). My plan is to have one with open sights, so 50-60-75yd accuracy is what I'm looking for -depending on my skill and the "correct" .22 round that it shoots well.
I realize some folks have Handi-Rifles because they're cheap (compared to a Thompson/Center or Ruger No.1). Others simply seem to enjoy "tinkering" with them.
I like the versatility of the switch-barrel single-shots, but also their very affordable price. Plus it would not be a huge $$$ loss if one was destroyed or stolen in a Katrina scenario or survival situation. And for truck/camp gun, or "SHTF" gun - my Survivor is indeed "versatile!" (with .223R, .30/06, .45/70 and 12ga abilities! Plus an adapter from McAce Sports will permit using .308W).