I'm glad I found you, I'm printing and assembling the same model. I'm currently sanding the pieces, I filled some defects with wood filler, for some parts I'm just using paint to reduce 3D texture. Plan to pain the internal silver.
I think the software is a great value, because you will loose more wasting materials and time. BUT... if you still don't want to buy the software there are some methods you can use, like taking a picture (with a ruler) of yourself and using photoshop to visually scale the armor and give those...
The best tutorial I ever saw on Foam Unfolding is from Pepsexy.
I made a complete guide on pepakura foam unfolding but is in Spanish for Latin american community.
The problem is the cost, and in our countries (Latin American) this technology is non-existent or expensive.
Other problem is that I'm trying to make an under-suit that can fit All Halo 5 armors, my plan is to cover some surfaces with "female" Velcro so you can build any part of any armor and...