Anti-sub belt with standard Caterham cushy seats, or...?

[Slonie]

Hi all, I've got 4-point OEM (Luke?) harnesses in my Caterham which have a provision for accepting a 5th/6th crotch strap in the buckle, but the stock seat bottom has no hole for them (nor is actually attached to anything, as we all know). Besides swapping to Tillets or the like, has anyone cut a hole in the stock seat bottom to allow it?

 

I suppose my other options for anti-submarining would include Schroth Rally Cross or even OEM inertia-wheel seatbelts. I was thinking the former may be the best bet with the stock seats. (I actually used to use them in my old track car with buckets but and still have one set, although it's ancient now)

[CarlB]

When I bought my car it had regular seats that had been cut for crotch straps. It worked fine, but wasn’t great for the seats. A good trimmer should be able to do a neat job.

[CBuff]

I think most folks just run the subs back to the rear bulk head. They come out between the seat bottom and back. You are kind of sitting on them.  This was my plan but the importer and the Schroth folks didn’t love the idea.  So my importer found an upholsterer who modified the squab with a cut out. Works great. You can always source another seat squab if you want to run with and without. I think it was a couple hundred bucks.