Last year I made a pair of Marfy 0680 trousers in a stripey stretch fabric. At the time they seemed a bit long in the body, and James did tell me I should have made them tighter. I'd thought the less than skin-tight fit was OK. Maybe it was OK, but the stretch fabric doesn't have as much recovery as one might have hoped, and they got baggy quite quickly after each washing, and got sufficiently bad that the trews became distinctly un-smart. I pondered what to do and decided that the first thing to try was to sew a new seam 1cm inside the present stitching line all around the inseam. This would make the legs tighter and bring up the crotch seam, making the body part shorter. To keep the grain (keep the stripes vertical at centre front and back) I also took 1cm off the outside seam below the hip/pocket/crotch. I'd thought I would probably have to take the waistband off and move it lower but, magically the whole fit was much improved. They were too tight in the thigh so I tapered the new seamline above the knee. Here is the result - still not radically tight - but I am hoping they will not bag out much more. I guess I can try the same trick again if they do... The photo is taken after one day of wear.
The lesson is that Marfy 0680 isn't that good a pattern for stretch fabrics. The extra ease feels right in non-stretch fabrics, although I might experiment with taking the crotch junction up an additional cm or so next time I sew it.