For those sails, and from the bottles on your bench, if you started with a 50/50 or 60/40 White to Radome Tan, that would likely get you a good start on the sails. Use straight Radome tan on the doublings and seams of the sails, and then dy brush them a bit whiter. Unbleached Linen make a good starting place, too, if tinted with white for good scale appearance.
Now, I must also admit a bias. I find vac sails useful mostly as forms over which to mould 100% rag resume paper if the scale is large enough, finer material, like rag vellum or tissue (packaging, not facial) in smaller scales. But, that's me; I find paper tolerates fine holes and stiching for attachment better than vac plastic.
The semi-glossy packaging tissue makes a nice material for making flags for this era, too.