Our guild, each month someone volunteers to select the BOM pattern, assemble the instructions and any fabric provided and they are sold for a $1 each. You are entered into the drawing the next month if you bring a completed block/s. The guild will reimburse the member for any materials provided if requested.
There is one volunteer/coordinator that keeps track and reminds the folks who is responsible each month.
Sometimes I participate and sometimes I don't. It depends on how I feel about the pattern/block that is given.
I haven't ever won, so don't have experience about putting them together but I think the size is a common issue based on the variety of experience you have of quilters and the difficulty of the pattern. I did one a few months ago and could not get it so points would not be cut off when assembled, so I didn't turn it in.
My guild has its quirks but I have made a few wonderful friends, so I can overlook, as it happens with all organzations. If I were you, I would suggest a change if possible, or just don't participate in that part of the guild.