Wow, did not realize they were that big, but you are right!!! (of course you already knew that!!)
to convert to 1:29.... feet times 12 divided by 29.... or feet times 12/29 or feet times .4138
7/16 = .4375 pretty close... but rounding up to 72" and using your conversion gives you 2.63", using 69" and the proper conversion is 2.38" so there is really a bit more difference.
BUT, I'm sure it will look great!
Lots of pictures please!.
Regards, Greg