Hi Tim,
I see you already found the logo dimensions in the Owners manual.
I am attaching a Powerpoint file that may be off assistance to you regarding the Nonsuch type style..
The Nonsuch decal on my 1987 N30 was worn away on both of the cabin sides.
By taking a photo of each with a ruler taped in place I was able to recreate the type style of the logo.
I can't say it's an exact match but it is as close as I could get under the circumstances.
You should be able to scale it up or down in size to meet your needs.
I hope this is of use to you and if you do have shirts made please post a picture.
Sounds like a fun project.
Cheers!
Jim Krzyzewski
Toyger N30U 422
Port Ludlow WA