So I'm trying to mount an eleven foot red oak plank along a wall in my bedroom with three brackets. The apartment I live in was built around the 1920s. I recently renovated it and didnt make note of where the studs were. They seemed to be sporadic. My issue is I cannot find the studs because behind the drywall are wood battens (that's just the term I use) and those seemed to be fastened to the studs that were behind them. I opened up the outlets to see what side they were fastened onto the studs by but that didn't help. The wall on the right adjacent to the wall with the radiator is the one I'm working with. See the attached picture. Any tips to help me find the studs would be greatly appreciated.