Try fiddling with these values:
With “Outward… in space” set to 3/8 spaces and “Outward… on staff line” set to 1/4 spaces I get these results, which are better but not perfect.
It strikes me that a one-size-fits-all setting is never going to work here, because the arp line is designed in such a way that you need a complete twiddle (technical term?) for it to look right.
In answer to your request: are you aware that once you have one arp line in place, you can alt+click it wherever you like? I agree it’s not as quick as selecting whole bars (which is presumably a difficult development task that needs to consider multiple voices) - but it’s much quicker than going Shift+O arp Enter multiple times.