The best thing to use to get things sized properly for 3D printed costumes is a program known as Armorsmith Designer. It will allow you to create an avatar based on your body measurements which you can then you to enlarge or reduce the stl files to fit. It runs about 40 bucks but it’s worth the investment.

Rotary tools are great and very useful for kit buildings (cutting/sanding/drilling). You can often get a decent one for cheap. Powered sanders will take the edge off quick. You can also tape some sandpaper to the table and rub the armor on it until the excess edge goes away. I'd really recommend you sand/file it down. For your comfort and overall kit accuracy. I think you'll be much happier with it.

Went to an armor party over the weekend. With a lot of help from Stryker and Delta, we cut and sewed all the elastic straps and put the velcro for the knees, forearms, and biceps.

Thank you very much.

JB Plastic Weld is what I used.  Make sure the surfaces are clean and dust free before applying the weld. As for placement, I recently discussed this in another thread and posted pics on where my reinforcements were placed.  You’ll need to apply heat to the reinforcement pieces to soften them up so that they will conform to the shape of the armor.  Of course you’ll want to just apply the heat to the reinforcement piece apart from the armor and not directly to the armor itself.