The alleged utility of perserverance

40cm rack struts with a single 90° bend

Repurpose unsatisfactory bar tape to muffle the thumping

Dill Pickle bag on the rack

I still don't know that it will work, in the sense of no ping noise after a substantial rolling distance, but it might.

(The thumping needs muffling because it's a big bag with a plywood bottom stiffener, and one can never winch the straps tight enough to prevent all movement when one of the impressive array of road hazards manages to kick one's front tire good and hard.

Mid-fork front light mount

Didn't leave a way to attach this particular light to the Mark's Rack, at least not without a metal-fabrication exercise to produce some kind of stirrup mount for the (obscured by bar tape) front tab bolt hole.  I nigh-certainly need to mess with the light angle and wire restraint but this seems simpler all round.