Patterns: Eagle's View Men's Waistcoat, 18th century version, with alterations.
Fabrics: 100% wool, tomato red, tropical weight. 100% linen, natural, medium weight.
Waist: 37-39" (back lacing to fit)
Firstly, I really like the Eagle's View patterns. They're simple and lend themselves well to alterations. The pieces are properly made and meetup correctly (a problem that, sadly, happens too often in indie pattern companies) There are a few downsides, though, but nothing that the intermediate and above sewist can't handle.
1) The sizing comes in a few wide ranges. For the waistcoat, the chest goes from 38 to 42 in one shift, quite a jump, but someone skilled with dealing with patterns knows how to mark "between the grade lines" and adjust fitting accordingly.
2) The instructions can be a tad confusing, and the methods given too modern. Again, if you're already familiar with 18th century construction techniques, this is something you can just ignore and assemble the garment in the manner you like rather than going to the pattern instructions.
3) In keeping with the simplicity of these pattern, a possible negative for less advances sewists is that there is nothing in the pattern or instructions about interfacing, interlining, front facing, or any of those little construction details that can make or break the silhouette of a period garment. Again, if you are already familiar with such things, you can just add them (I highly recommend The Cut of Men's Clothes, which contains many diagrams showing the locations of proper padding, interfacing, etc. on 18th century garments.)
As for alterations, the only change I made to the pattern itself was putting the shoulder seam back to a more 18th century correct position. Modern shoulder seams tend to be straight and high on the shoulder, while in the 18th century they did a sharp angle to the back, creating an 'A' shape effect on the back. Otherwise, the pieces are unaltered.
Interlining & Support
Waistcoats are deceptively simple (i.e. not simple at all). In fact, more work and "extras" go into a men's 18th century waistcoat than into a lady's full caraco jacket. There's just a lot going on "behind the scenes", and it's all necessary for a good fit and lay.
The area of heavier interlining is meant to cover where the buttonholes will be, as well as give a stronger area for the pocket hole. As for the shape of it, the reason I prefer this rounded kind of shaping rather than just a straight strip, is because anything straight under the surface will create a natural folding area, and the interlining would show itself more that way through the front layer of wool.
Also, by extending the heavy interlining wider in the chest, you create for firm shaping to help fill in that "hollow" area that most men have just above their chest and before the shoulder starts.
2) If you aren't doing a full flat interlining, you will have to loosely tac stitch your heavy interlining area to your outer fabric. Use a gaudy contrasting thread, so you don't miss it later, and make the stitching ridiculously big, like 1" wide. These tac stitches will stay in place through your buttonhole work, the pocket flap attachment, everything in order to keep the heavy interlining from moving around while you're working. In fact, taking out the tac stitches from the outside should be the last thing you do after completion.