Maybe you could invent an "autopost" function, that sends your questions every 20 seconds if you are not there when the forum day or the chatting hour happens, changing the question just a little each time, raising it´s value...
I say it again. A chat would be really difficult and saying the contrary would be made by someone who doesn't go on the chat during games. Small, overcrowded, flooded and of course trolled and flamed. Forums are far more manageable.