Probably won't find him during the day, he'll be immobile hiding in his spot. Best chance will be late at night when he's active.
Try getting plastic bags and ball them up and put them around places that might be high traffic. The idea is that if he crawls over it, it'll be noisy.
Remember that these guys are terrestrial, so they'll be traveling on the ground.
You can put a bunch of plastic cups (like Solo cups upside down) across a threshold so you can see if he passed through that way.
I read stories about a bp that was lost for 3 months before he was found...the fact that their food/water needs are pretty forgiving is good news.
I wish you luck, let us know where you find him!![]()