Alrighty here are your measurements. I've attached the .armor file in the zip of this post as well.
You can buy Armorsmith for $40 here:
Armorsmith Designer is a tool for creating and constructing costumes with ease. With Armorsmith, you can design your own avatar and customize it to your liking, then attach 3D model costume parts to bring your vision to life. When you're ready to get started on your costume, Armorsmith can turn...
thearmoredgarage.gumroad.com
Armorsmith Measurements
Height - 72.25
Chest Circumference - 33.5
Neck Circumference - 15
Shoulder Width - 16.5
Arm Length - 23
Bicep - 10.5
Forearm - 10.25
Back Length - 28.5
Waist Circumference - 29.75
Hip Circumference - 33.5
Inside Leg - 30.5
Thigh Circumference - 18.5
Calf Circumference - 12.75
Head Width - 6.375
Head Circumference - 23
Foot Length - 10.75
If you want to scale the armour yourself, that would be great! I can help and give tips if you'd like, but it's a good idea to become familiar with Armorsmith yourself.
Also, I'm going to go look for that halo reach under suit file. It was used in
this writeup about making an under suit. If I recall correctly, the original creator of the file sold the files, but I don't know if they're available anymore. If I remember correctly, there's some resources that can be found from the Halo Archive and unfolded into an under suit template. I'll send whatever I find!
Happy scaling! Remember to use the foam-optimized files in that zip folder.