That was a great deal, paid full price for mine $234 I think but still feel it was a good deal.
I did the elbow mod for awhile, but once I got a tuning plate, also from BBQModders, the elbow because useless and actually cause a temp difference from top to grate level, also seemed to cause too much smoke flavor, bordering on bitter.
Never used a water pan, some do I guess, but I always felt they were mostly for vertical smokers
I also have the Maverick 733 and pretty much just use it, never changed out from the temp probe that came with the smokers, because the mav is all I use, sometimes with chicken I'll double check when done with my lavatool instant read. I always have one of the temp probes from the Mav at grate level and one in the meat except for ribs, those I do by time
I did drill a 5/16" hole just behind the smoke stack and slightly above grate level, for the Maverick probes, they will both fit in the one hole putting them through one at a time and reach anywhere in the CC, then just hang the sending unit on the handle below the stack.
You'll probably fine that using just wood works much better in the highlander, I use maybe half a chimney of briquettes just for a good bed then a mini log or two to get going once I have a good fire going and some good coals I'll close the fire box and CC lids to start bring up to temp. Mine loves 240-260 range so that is what I use most cooks, I have never got my highlander to hold 225, doesn't like to do it...lol..Use the FB vent to get the temp stable. Once stable usually after an hour from fire start, put another mini log of you flavor wood you want to use and put on the meat. Highlander with all the doors sealed and tuning plate will use a mini log every hour to hour and half with the FB vent open 1/4 to 1/2 inch, once in a great a while I'll need to close down the stack vent half way if the temps start rising to much. But that is my highlander yours might be difference, make sure you season it good before your first cook. Good luck with it, I love mine, just took a little time to get use to it.