I probably did this all wrong. But I found a way to do it that was a pain. I created and eps fil and reloaded it. I created a new blank RGB image of the same size and cut and pasted each channel in as a layer. Then I did a select by color (ie black) on each layer and filled with the correct color. Then I did an inverse select and cleared out the white to transparent.
To combine like colored channels I cut and pasted between them.
I created the image by creating spot channels and drawing in each one. Each channel itself is black and white but represents a color. When I was done, I had 8 channels for a 3 color print. When I switched to rgb mode, it went crazy.
I found out that in multchannel mode you can only save as psd (photoshop) or DCS (eps). I know there must be a simple option to convert correctly as I accomplished it doing a very mechanical proceedure.
I just need to understand this tool better. This was my first time using channels and it was pretty cool to work with them and not rely on the filters for everything.
The only way I know how to convert a SPOT multichannel file into a RGB or CMYK file is to cut and paste each spot channel into its own Duotone file.
Select 'Monotone' in the 'Type' scroll down menu and specify your the matching pantone color to your original spot color. Then flatten image...'Select All' and copy...then create a new RGB or CMYK file...paste the monotone art (it will fit exactly). Select 'Multiply' for your layer blending option.
Repeat for each spot color...flatten layers and save in what ever format you need. It seems like alot of work, but it goes really fast once you've done it a few times.