Excellent job Sir Ian! I will have to add this to my 'TO DO' list! Do you prefer the fit and function of this over a Pourpoint?
If you're wearing a properly tailored arming garment, the fit and function should be identical. That was the point of this venture into experimental archaeology, to see if I could reproduce something as comfortable as a properly tailored arming doublet without the doublet. Having just vetted both this (with a required modification, the arming patches will need to be relocated to the inside in keeping with the aesthetic of medieval leatherwork), and the new hand sewn CdB, I intend to try each out for a full day at MTA this weekend and compare.
If for some reason the leather girdle functions better, then it would be an indication that my CdB has something wrong with it's tailoring. I would prefer the girdle as an alternative, not a replacement for a proper arming garment. From the historical side, we know that armed men were using arming doublets to suspend leg harness. We also know that there was some other means of suspending a leg harness since there is imagery of men in harness with clearly no visible means of support on their exposed doublets, yet their leg harness has to be supported by something. We may never know what that something is, but this is one of the good guesses. For earlier periods when there was no arming doublet, like the age of maille, we know from text that some sort of 'belt' or 'girdle' was used. But what it looked like, no one knows. Again, this is a good guess. If it works as intended it will certainly be a superior alternative to most of what the people wearing maille are utilizing right now (c-belts, thin belts, vests etc), and in keeping with the vague sources.
It would also work very well for a person interested in wearing a maille skirt. You can whip-stitch a maille skirt to the hem of the leather girdle, and at the same time use it to support your leg harness from the inside.