Thanks for the responses - the shoulders are in the cockpit area and my confusion was due to seeing some Guillemot forms in pictures I found through this forum that didn't seem to have them.

Regarding using EXCEL with a plotter - Nick's explanation is good, but not 100% complete - for one thing, I found that I had to use radians when plotting his 70% reference line - his description worked with degrees and had the trig backwards.

The bigger issue was properly scaling the plots. After failing miserably with EXCEL, I tried using PowerPoint and Visio and found that both of them were both inaccurate and hugely painfull to use. I went back to messing with EXCEL and eventually created a VBA Macro that made all of the plots the exact same size and that also applied vertical and horizontal correction factors to each plot. MicroSoft says that 1 inch = 72 points, but when I sent a test plot out to my plotter, I discovered that 72 points produces a very funny looking square.

Here's the corrections I used for my plotter:

vpoints = 80.80271459 'vertical adjustment

hpoints = 70.11177527 'horizontal adjustment

Results seem to vary with the equipment, so if you try this, first send a grid of 10 x 10 72 point (alegedly 1") squares to the plotter and then measure the actual width and height with an accurate ruler. Use the results to determine the corrections for your plotter and then perform another test. After a couple of iterations, you end up with insanely accurate results (a lot more accurate than I expect my woodworking skills will justify).

If you would like a copy of my spreadsheet (including the Macro) send me email and I'll shoot it out to you - my address is EdPerrault (at) ATT (dot) NET - unless I get a lot of spam, in which case it'll quickly be something else.

EdP