I am starting from RAW files taken on tripod with a panoramic head. Talking about Photoshop CC2015.
I'd like to know if, in order to produce more accurate results (and given the barrel distortion at the wide angle used), I'd be better to stitch:
1. Directly in CameraRAW by selecting multiple files and then choosing create panorama
2. Directly using Photomerge and selecting correct geometric distortion
3. Firstly correcting each shot for barrel distortion in CameraRAW, then selecting them all again in CameraRAW after they all have an associated XMP file (which could hopefully keep the barrel distortion correction associated with each shot when merging them?)
4. Firstly correcting each shot for barrel distortion in CameraRAW, exporting them in 16 bit TIFF then Photomerge them.
5. Other options.
Any input welcome, thank you very much
I have experimented both ways. As far as one being more "accurate" than the other is concerned, I don't believe there is any measurable difference. I created a panorama from (12) 24 MP Raw files. My computer only has 8 GB of RAM. I believe the panorama was created more quickly using Lightroom because there was only one program involved which left more RAM available to do the processing. One advantage of using Lightroom or camera raw to create the panorama is that the resulting panorama file is saved as a DNG file. If you are using a camera that has multiple profiles such as camera vivid, camera standard, landscape, etc. switching profiles on the panorama will have an effect on the image. Photoshop is going to create a TIF or PSD, so you won't have the option to switch profiles.
After having said all that, I think the best thing for you to do is to experiment and decide for yourself.
I'm not sure if it's still the case, but the two methods are different, and can produce different results. Some images might stitch better in ACR/LR and other in PS. As Jim mentioned, you need to experiment. So far, I've had better luck with ACR/LR.