Could someone with better search fu than me please guide me?
Weber now sells a silicone port insert that will seal around the probe wires. It is part number "85037 - Grommet, gray, SMC" is is reported to be less than $12 shipped from Weber. Another option is a home made probe inlet from threaded brass electrical tube (like they use in lamps and in ceiling boxes). Cut a short length and add two nuts and washers and then make a hole in the WSM/mini-WSM. I would link to instructions elsewhere on the web with photos, but we can't do that anymore.
Take a look at the link below my signature line - it is an eyelet mod I came up with for my WSM, costs under $5, you can fit up to 3 probes through each eyelet, and you can place them wherever you want.