1st Gen Camper Shell Attachment - Need Clamp Advice (Leer 122)

Hi folks, wanted to see if the considerable knowledge pool here could help advise on the optimal way of clamping a new (to me) Leer 122 75K. Should I try to clamp to the bedrails through the square holes that have been cut into the bedliner already in order to access the tie-down points in each corner? If so, is there a clamp available out there that can go that distance--current clamps that came with it are too shallow to get a good clamp on the bedrail since that hole is cut lower and there is a little lip on the shell that requires the clamp to come out at an odd angle. Also, any lower profile more sleek clamps out there? It's weird that these fancy shells require these hulking block clamps--I have small bolt-style J clamps on another junkier shell on an older truck and they are much smaller (still effective though).

Alternatively, could go through the round holes in the bedliner that are for the locking cams to hold the bedliner to the rails. Trouble there is they happen to fall right in places where the shell has an extra little bit of width so the clamps have to be positioned awkwardly to get around it.

Also could cut more holes in the bedliner if need be. Although would be nice to use the existing holes if possible, ideally the corners since I think that would make a better seal.

Grateful if anyone could share their wisdom or point me to a clamp product/arrangement that's worked well. Thanks in advance.