Combine RGB in Beta 26 not working for me (user error?)

I have some OSC data of the Heart Nebula, and recently collected some ZWO DuoBand data as well.  Having seen some brilliantly done shots of this target with similar setup, I'm trying to reproduce them using the RGB Combine tool.  I've followed multiple tutorials on how to do this and am getting nothing but crap.  The combined image looks almost identical to the RGB alone version.  Clearly I'm doing something wrong but for the life of me I can't figure out what.  I've attached three shots below (first two are stacked only, no processing; third is the results of extracting the R, G, B, HA, & OIII and "RGB Combine").  

OSC data

DuoBand data

"RGB Combine" results.

Following the tutorials I'm confident I have successfully extracted five registered and normalized .fits files (R, G, B, HA, OIII).  It's the combining part that has me stumped.  The tutorials provide instructions to mapping the files to colors with the OIII channel being mapped twice (B & G).  However the latest version (Beta 26) doesn't ask me to assign a color but rather what filter was each channel shot with. It also asks for a Formula that is never addressed in the tutorials.  Taking a guess I selected RGBHOO and mapped the channels as such:

R Channel: Red Filter
G Channel: Green Filter
B Channel: Blue Filter
HA Channel: HA Filter
OIII Channel: OIII Filter
OIII Channel: SII Filter

Clearly this didn't work.  I'm out of altitude and airspeed at this point. Any guidance would be greatly appreciated (I'm still very new at this so any procedural help must not skip any steps or assume I know what I'm doing in way 😎).  I would be willing to upload the five grayscale color-separated files.  

Thanks!