I found a bug that allows you to use any material at any level. To do it you have to be in the character customization screen and hover over the material you want selected while the clock is counting down to the next game (I've only tried this in Dominion). When the time runs out and if you're still hovering over the material you want to use, your screen will transition to the character select screen and the character you customized will have the material you hovered over equipped.

P.S. This was an accidental discovery and I tried it several times to see if I could replicate the bug. Also I only tried this on the warden and lawbringer but I assume it works for all characters. Just thought this bug should be fixed that's I am making this post.