Note, I have also tried doing it this way:
1. Export A & B as layers to Photoshop
2. Apply luminosity masks and merge these two layers to a final image, C
3. Save C as "C.psd" and then open it in Lightroom
4. Apply Lens Correction to C.psd
I am unable to find my camera profile in step 4. Maybe because it's a psd file?
Also, since it's a psd file a lot of RAW info is lost.
Have you considered using Merge to HDR in Lightroom? (select the images, and press Ctrl/Cmd+H)
That way you wouldn't have to use Photoshop at all, and would only have to use Transform once, on the merged image.
After applying the Guided Upright to one of the photos, just Sync the Upright Transforms to the other photo(s), by selecting both/all the photos, making sure your corrected image is the most selected, then click Sync, then make sure Upright Transforms is the one item selected from Transform. Obviously if you've made other adjustments to one and not the other you can selected those others as well, but Upright Transforms is the one that copies across the Guided Upright adjustments:
No I do not want to use HDR. I want control over which area gets merged hence I am using Luminosity mask
This is exactly what I need! Thank you.