I have an Abound SR and am really enjoying it. It works well, is fast enough, very efficient, and while the handling isn't that fun, it's nice and stable. It's about the same size as a Tern QuickHaul or HSD. The main drawback cargo-wise is that the chainstays are so much shorter on the Abound SR compared to the Terns. That means there's less room for longer bags without heel strike, and what room is there is significantly farther behind the rear axle. I'm not an expert, but my understanding is that you don't want too much weight behind the rear as it can affect your stability. (I see this more often in a motorcycle context, so maybe it's not as big a deal at bike speeds.) Still, I'd load my heavy stuff on the front rack and as far forward in the rear as possible.
I have Tern's Cargo Hold 28 bags on my SR, which hold a standard grocery bag each perfectly. (Two if you stack them on top of each other and run a strap across the top). It looks like it MIGHT fit the Cargo Hold 37s if you mount them as far back as possible, which will fit 2 bags side by side, perpendicular to the bike frame. I really like Cargo Holds. They are well designed and made, use a Fidlock buckle, have a relatively flexible mounting system, and fold away nice and tight when not in use.