Well, that sucks. The video on their website says the overall length of the rear support is 42 in., but did not specify the hole spacing. If you measured from hole to hole, then my already cut piece is going to be too short.
The car is a 66 Beetle convertible, but I’ve put a 62 Beetle body on a 71 pan before with no problems, so I don’t think there’s any difference on the Beetle pan.