the guru and the ique both work very well with the wsm. If you get the maverick, the Ique will get the job done (the guru comes with the food probe).
If you get the grommets, get the larger ones since the 1/4" are too small for the new maverick probes.
I went with sand and have second thoughts becuase of the additional weight. I am looking for a clay pot, r if I can chisle the sand out go dry. Water is fine, but I like to leave my cooker alone and not have to worry about the water pan running dry and spiking the temp.
Pick up the weber 18 charcoal grate. Lay the 18 charcoal grate so that the grates are 90 degrees for each other. This limits small hard wood charcoal pieces from droping through.