The guy thats makes these lives here in paso robles as do I. I delivered dazzos to him and eventually bought me one. I guess the "advantages" would be not having to reserve and haul your stuff to the park, still having a cool way to do some grilling AND best of all, still getting to do it on a Weber!! (and the caliente stacker isn't true santa maria style)
With Santa Maria, it's about the flavor and not the grill. The red oak firewood is not even readily available outside of the central coast. Can't find it here in the Bay Area. Seasoning is salt and pepper only, maybe garlic.
I'll offer some thoughts.
I wouldn't get too caught up with red oak and just S&P or any notion of being "authentic."
For wood...Lump is a good substitute, but the better option would be to cook wood down to coals and cook over that. In the Central Valley, everyone...including many comp cooks and caterers use almond wood. It burns hot like oak and has a medium/neutral flavor contribution. Lots of almond trees popping up in Australia...so something for you guys "down under" to try. If you are in the south and can't find seasoned oak or almond, use pecan.
Most cooks I know who make tri tip in the Santa Maria style (including people on the Central Coast) incorporate garlic in some fashion or another. Some of the old Californio recipes even call for garlic (in the rub or baste), so something to keep in mind. That video you linked was pretty cool. He mentions Piquito beans. And as long as I can remember, I think I have had Piquito beans once. They are an heirloom variety that are around $20 lb. Most everyone uses either red beans or pinto as a substitute.
I think BBM's method of using the WSM is really interesting and something I want to try.
I think the Santa Maria attachments are pretty cool, but you can make a killer tri tip without one.
