I do $1000-$2000 at a time on two Redcards. Most of the time the service desk employee does $1000 transactions, but occasionally one will do $500 at a time because they don't know how to do split payments. There's usually not a service desk line at the Targets I go to. I don't use the checkouts.
I try to reserve Target for OVs, so my loading mostly depends on whether there's stock at the two 7-Elevens I frequent.