As I remember it, Revan had his own mask. It had no t-visor, it was more of a slit visor, like that of a royal guard. Canderous had life support built into is armor because he never took it off.
As for the discrepancy between the mask, perhaps the mask we see for mand'alor is one of his armors or maybe a formal/ light armor. The mask retrived by Canderous could have been mand'alor's heavy /battle armor. Also theres the chance that Ordo did indeed retrofit the mask for his own purposes. Mand'alors mask could be there under all the changes. the visors are more or less the same shape.
Your armor is fantastic nervod. I cant wait to see how your helmet turns out. Keep up the good work.
oya manda!