I used a Bronze collared bushing similar to this...
and a collar nut similar to this on the inside...
[URL="http://www.ruland.com/ps_collars_shaft_msc.asp"[/URL]
I can get the specs on this if you want, I cant remember the sizes off hand. The probes have to be inserted one at a time. You do the meat probe first then the pit probe. Perfect fit! My criteria were simple finished look, easy install, small hole to be drilled, heat resistant (no plastic or rubber), and lastly affordable, which these pieces probably cost me a tad over 5$.