Catalina 350 International Association

I want to put a padeye on the coachroof. My question is how thick is the roof? I do not like the idea of removing the headliner to gain access for a backing plate so instead will drill out oversized holes for the screws and then fill with 5200 to allow the screws to bite with no leak risk.

Any comments or advice on this? The padeye will not be under any appreciable load so bolts are not a must have requirement.

FYI if anyone needs to know I used 3/4" screws with a coating of 5200, the padeye was 1/4" thick and I drilled the exact depth and size I would need...maybe the last 1/8" was balsa, so I think with hindsight I could have gone an inch comfortably.