I thought I'd do a bit more detail on the finger assembly procedure here.
In order to not have too many pieces on the bench at once, I worked my way across the hands, starting with the fourth fingers. The temporary leathers were removed from the knuckle strip, and all the "cannons" placed in the proper order. I traced around the plates with a pen to get an idea of how much sewing margin there was and how much more would be needed.
The shortfall was added to a tracing of the leather, and I spent some time fussing over whether the lines were right. The sides of the finger leathers should be pretty straight, and the whole thing should taper. The tip should be graceful and symmetrical.
I cut out the new template, and spent a bit more time fussing over whether the lines were right. Then I traced out a pair of them on the leather and cut them out with scissors. I left the pen lines on the waste.
Using the temporary leather and a scribe, I transferred the hole locations. These will be just "suggestions" and the true locations will be determined directly from the plates.
I set each plate in turn on its leather and marked the holes with a ball point pen.
The holes were punched with a small tube punch and carpet tacks installed. The tacks were mostly cut off rather short, so as to leave just enough for a flush head in the countersunk hole. The finger tip rivet was treated a bit differently, though. It will be exposed, and needs to end up with a smooth head that will not catch on a cleaning rag. They are cut a bit longer and finished up with a concave punch.
In spite of my best efforts, the sewing margin was a bit uneven and excessive. I took this opportunity to trim it a bit.
Meanwhile, the knuckles have been waiting in ziplock bags since the rest of the armor went off to be blackened. All the parts are punched with identifying marks, but I labeled the bags as well. They will be gold plated off camera.
Before the knuckles go on, the exposed ends of the rivets/carpet tacks need to be blackened with a dab of Oxpho blue. Since I am dipping right out of the bottle, I use a fresh Q-tip for each set of fingers. I don't want to contaminate the stock by double dipping.
The hole locations for the knuckles are marked with a pen, and the rivets are peened up like the ones on the finger tips. They will be left "white", though.
That process was repeated for each pair of fingers, and the resulting assemblies were riveted onto the knuckle strips.
This is a temporary assembly/reality check. I want to make sure everything is working correctly before going further.
The next step will be to sew the fingers to the gloves. Depending on how my right elbow feels in the morning, I may defer that task for a couple of days and work on cleaning up enough of those brass caps that Rene K sent me to finish up the helmet.
Mac
A sandbag will sometimes work as well. If you have a big rivet set, or a punch with a hole the size of the rivet head, that can be put in the vise to support the work. The tool should have a cross hole in the shank to let you clear out the dead rivets. This method is better for flatter work than finger lames, though. It can also be a bit harsh on the leather, if you intend to reuse it. 
I've come in to waste time while the bleeding stops. 
