StarTools

It all depends on how you'd like to color/use your Ha data. Ha data doesn't correspond to a displayable color, so you're going to have to decide on how you want to represent Ha in your data.

A typical usage of Ha is to have it influence both luminance and red channel information. If you want to go that way then, the Layers module is indeed an incredible flexible way to make those blends.

You'd have to be able to save your work for this procedure to work this won't work with the demo version).

The procedure is the same for red and luminance;

• Load the red or luminance data as a new image (e.g. it will appear b&w).
• Optionally perform a screen stretch ('Stretch') if you'd like to see what you're doing a little better.
• Launch the Layer module. Open the Ha data (it'll be loaded as the foreground layer). Make your blend using a blend mode that you like. There are a few you could try - 'Multiply, Correct Gamma' is one of my favorites as it helps the luminance layer to benefit from the Ha's layer reduced star bloat.
• Save the result as your 'new' luminance or red data.

Once you have created your 'new' luminance and red data this way, composite them as usual using the LRGB module.