I have spent some time on this problem. The first conclusion I came to was that the mid-fork mount isn't really weight-bearing. It keeps the rack from tipping forward or back, that's about it. My bike doesn't have these holes, but it has a steel fork and I bought threaded inserts to install instead of using the (Axiom) u-clamps, but then decided to look around some more.
At that point I found Pelago racks. They come in steel. They mount on the dropout eyelet and the fork crown. You can get a small, medium, or large (pizza) platform for the top, which I really like! (Got the medium). Their low-rider rig is in the form of replacement legs for the normal, non-bag mounting platform rack, and they use the same fork-end holes, no mid fork mount at all. Not everyone has the low-rider accessory legs--you have to look around.
So what you get is a nicely-designed steel rack, securely mounted, with your choice of platform sizes, and a low-rider below that. All for a pretty reasonable price. And you don't have to drill any holes in your steed.
Last edited by mdarnton; 02-05-23 at 06:43 PM.