Full body shimmer

I've added shimmer to larger areas on dolls by just sealing, then brushing on the pearl powder like I would pastels and then sealing again. You could just add it in when you blush her body, since you'll need to seal the body for that anyway.
Just keep in mind that the sealant will dull the shimmer, so you might need to do multiple layers of pearl powder to enhance the effect.

 

If you want to use the spray method, rubbing alcohol might dissolve the sealant so it's probably not the best thing to mix the shimmer with. With distilled water it would be safe, however, just make sure you let it dry off completely before spraying more MSC on top (it's infamously bad with any humidity).

I would also say it's the most practical to just use shimmer powder as you do with pastel like said above. You might want to try it out on a smaller area (like the headcap) first to see how many layers you'll need to do for the effect you want

 

I used pearlx powders to blush a CPDelf whose white resin had that greenish tinge as she aged. As LupusDarkmoon suggested, we sprayed her with MSC & then I just brushed on the the powders. Used lavender for my detail blushing, then another layer of msc. Then brushed the shimmer powder to give her a glow & distract from the green. Play with it on the headcap to start, as the powders do brighten when sprayed with the msc so practice a bit before you tackle the body.