I never boil any wood that I put in my tanks. In this case, I think I'll keep it floating. I hope it will keep floating, or else I'll suspend it with a string.
No I did not tie the moss to the wood, actually I don't want the moss covering the wood, I think it is a waste for such nice wood.
Actually I tried angling the substrate, but it got messy and complicates my effort to partially bury the filter intake (it's quite long).
I think I might get rid at least most of the moss, get new plants, and start over.