Might be able to modify the head of this easy enough to make the head fit with a slotted head to screw it down.
3/8 × 16 thread is normal weight bolt thread .
https://www.zoro.com/zoro-select-thumb-screw-38-16-thread-size-round-plain-nylon-43100-in-head-ht-2-in-lg-5-pk-0937516200t/i/G3383326/