I think I would postpone the Magneto for now to recover some space to get rid of all the 2hp modules. You will probably hate trying to patch and tweak all of those little ones. In my experience, tiny modules should be used very sparingly to fill a gap here and there. You could get something like an FX Aid XL or an external tape delay pedal to use that space for other modules that you are going to want and need. The Magneto might be a good addition to a second Mantis case, but I think it's taking up too much space for now. In fact, you could get 2 FX Aids, and eliminate the Magneto and Erica Black Hole DSP and have even more room without losing much of the sound and fun of those hp hungry effect modules.
Just some thoughts I have as I look over this. Have fun and good luck!