Hi all plastering noob in need of help. We have a re skim job to do at home. we have a cavity wall that had been clad with boards all around as there was a door and caseing originally there. This was removed and just wrapped with board beaded and skimmed. Now we need to rekim. i see we need to place an angle bead on the two front corners. But what do we put on the back corners the meet the internal wall? Angle bead would cover the back wall not being plastered. Do you use a stop bead? If so there would be a small grove where it joins the old angle bead. Can this be just filled with caulk? Hope this all makes sense.