I've tried enlarging and refining the drawings but they still remain illegible.

If you want better readability you have to upscale the drawings. If you upscale the drawings you're gonna get jaggies. You may be able to read text better but scaling from the upscaled drawing will induce errors. If you wanna go this way you need to find a utility that minimizes jaggies on upscaled content. I built my F1 using Harvey's survey drawing ... upscaled to about 3 feet and washed through a demo version of a utility called SmartEdge2 ... but it doesn't seem to be available any longer. Perhaps you can find an alternate. GIMP might be worth checking out ... addons are available and one of them might work if there's nothing in the stock package.

Right off the bat looking at the Hung drawing it looks like the OAL is stated as 14'-9" ... but if you add up he dimensions it's 14'-10.5" ... but Harvey's survey drawing says it should be 14'-1.75" ... so I wouldn't use the Hung drawings without doing a comparison to the survey.

When I scale measurements off a drawing I don't use the vernier. The reason is that there are often slight discrepancies between top, bottom or side views and these are magnified if you upscale the drawing. Instead I pick a measurement I trust ... usually OAL ... and use that to create a unique scaling factor for each view. This keeps me from chasing my tail (as much) when I'm scratching my head when I find measurement deviations.

Ken Blanton