Not sure I follow you. Healy has the mics side by side, one facing left, the other right, angled 180 degrees apart. That angle and the near-spacing give it a very wide pickup angle that de-emphasizes the center part of the image which works well on-stage. Both mics are the same distance in the forward/back dimension, what do you mean by 'rear mic'?
OK after thinking about it I think I can picture what you're doing now, Healy Method generally uses side-addressed large diaphragm mics, one next to the other facing opposite directions. I assume you are using small diaphragm end address mics and the bodies/cables would interfere with the narrow spacing?
I could be wrong, but as I understand it part of what the Healy Method relies upon is the tendency for large diaphragm mics to become more directional at higher frequencies when set to the omni pattern. A small diaphram mic will be more omni than that may translate as less separation between channels in the higher frequencies.
How far back from the stage will you be? I'd suggest spacing the mics more and angling them less from an audience location.