just sharing my solve for this on another forum if that's agreeable?
https://electricbikereview.com/forums/threads/radmini-cargo-rack-alternative.32319/#post-420492

the rack shown in photos looks VERY solid but our mini's are for younger folks where we need the seats as far down as possible which made the seat-post mount approach less desirable.

Quote from: Cru Jones 33 on July 21, 2020, 06:50:41 AM
Not sure why you would want to buy anything other than the rad rack...

the main reason is the radpower racks for radmini seem to be perpetually out of stock
and those tubes are well reported as too fat for many popular pannier bags

anybody finding anything confirmed good out there yet?

to add to my annoying constraints these radmini's are for kids where i need the seat as far down as it'll go, which makes "standard" height racks like the Ibera in original post pretty iffy... if it were for an adult i'd look at the Ibera height as a positive that the bags aren't so close to the ground.