Front seat belt attach hole

Hallo. After more than 5 years since kit purchase, my RV4 in nearly ready.

I bought a Crow harness set (front and rear seats). The rear belt attaches have an AN4 hole. The front ones have a wider hole (maybe AN5). I can't understand why.

However, before drilling the aluminium bars on the fuse floor, I would like to know if it is better to drill the wider hole or the smaller one and use a washer to accomodate the space between the bolt and the SS Crow attach.

DWG doesn't call for the hole diameter, even if in the rear seat belt section calls for a 1/4'' (so, AN4).

https://ibb.co/vjG40W9

https://ibb.co/XFDr7ZH

Edit: I found a similar answer in this thread: Capflyer suggests washers instead of enlarging the hole:
http://www.vansairforce.com/community/showthread.php?t=84647&highlight=crow+belt+hole+diameter

I believe the larger holes in the front are to accommodate a bushing that allows the seatbelt attach to pivot, I have the same setup with the crow harness, but will have to go look at my installation to verify.

Maybe

I ordered some AT6 (hard aluminium tube) from Spruce: 6/32'' i.d. 1/4'' o.d. Will make the bushings from that.