Seat Belt size for '68

[crazeetxn]

All -

I've searched the forums and figured out where I'm going to buy them from. Question is, what's a good size to get?

Getting 1 lap belt for the middle - options 60",74" or 90"

The 3-point harness is 115" so no option there.

I'm leaning on 74" for some wiggle room, but thought I'd check with ya'll first.

It's my son's truck. He's about 6', but smaller folks would be sitting in the middle.

Thanks for the help!