Roughing in a new shower
If the wall panel is 34---the flange is 1"--you now have 35"--yes---you will have a hard time drywalling that little 2 inch space----
If you don't have the option of making that wall wider----add a wood strip along side the flange so the area is flat---then add your 2 inch strip of drywall--use drywall adhesive---and maybe some finishing nails or staples to keep it in place until the adhesive sets up--
For corner bead, if needed, use a paper backed bead that is held by Multi-Purpose drywall mud.
I would avoid nails or screws in the board or corner bead--they will crack the thin strip.
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