I agree with Celtkhan. Start with a custom kit first before you even consider building a Canon kit, much less two. As for your plate material, and whether to fabricate the plates yourself or buy prefabricated plates, that’s up to you, your budget, and skill level. All of my plates are vacuum formed ABS plastic I bought from a vendor. The only piece I fabricated myself was my codpiece, which was hand shaped from ABS. Others 3D print their kits, though that requires a lot of sanding and filling to get rid of print lines. Some people even forge their plates from either sheet aluminum or sheet steel. The choice is up to you.