How long do you have to wait to place a cake on a fondant covered board? Would adding tylose powder speed up the process?

The board will dry hard in several days. You can put the cake on before the board is completely dry, just be careful of nail marks and stuff like that.

Yes, add tylose and its good leaving it overnight for use the next day.

Awesome. do you prefer to use fondant or different "papers" to cover the cake boards?

Deffo fondant nowadays

In a rush, I've covered the board and put the cake on it immediately. Be careful of making marks, as others have said.