Some extra ways to make the torso fit
*Press fasteners (sport+camping) which are hammered in a 2 leather strips which you glue and/or sew into the back. Give enough air and is easy to fastnen you need only one person to fast them.
Preparing the torso
* a mix of 2 inch elastic + velcro and a very thin bikeshirt (the black ones which are used by pro tour the France athletes. They are thin and they give loads of fresh air). Just glue and sew the elastic for the grip and use the velcro to thigten up further.
Gauntlets
If you have the soft ones use some soft foam to make them fit snugly and comfy. Use the foam which has diamonds pattern on the inside. It will give a lot of fresh air.
If you have the sturdy strong gauntlets. Search for a place where you can saw the gauntlets in half. You have un upper and lower part then. Use a piano hinge (you can surely buy them in some shops). Use the grey velcro (which is the strongest) or a good lock to close the 2 parts and use also the same soft foam to make the gauntlets more snugly & comfy.
The reason for the foam is that the gauntlets won't rotate

you understand what I mean. Because you want te blades on your arm not under your arm.