My Dodge Dakota, of all things, has a lovely sound at idle....I personally like that more than a booming exhaust at speed.
btw, my Dakota is a v6, yet still has a great sound.
The original exhaust is a 24" straight-through can, because efficiency and low back-pressure.
Thus, that is not far off what it should sound like (minus the hole in the end of the muffler) so it should have the slightly hissy thrbthrbthrbthrb at idle and the schwrb-rb-rb-rb-rb when it is revved or under load that you really only get from a sidevalve.
A sidevalve V8 sounds very particular with a straight-through exhaust, an inline 8 on a log pipe has a similar thrumming warble that I love.
I’d go for original unless it was going to be overly restrictive, in which case I’d go for something free flowing, but still quiet.
You’ve spent time and money getting it running right and the gearbox rebuilt, and have kept those stock, saying it’s not a performance machine it’s a lazy cruiser. Well, the last thing you need on something like that is a loud exhaust.