Looking for feedback on the IGT. We are thinking about using the following pieces for our outside cook-set. Three unit Corner set with a Double BBQ Box and the Tembo Tusk Skottle adapter for the other side. Giving us a cooking surface for anything we can think of , a small prep area and a place to sit. Will probably figure out a way to have a sink insert that collapses and the knife cutting board for the other open area.
i can't really give an accurate recommendation for your situation without knowing what cooking style you have, how many people you need to cook for, and how much payload/space you have for gear.
that being said... I can say you listed a double BBQ box, a skottle adapter, a sink, and a cutting board. if you want all of those in a frame, that will be 6 units of space. so the 3 unit frame will only allow one of your cooking methods, and a sink or cutting board in the frame.
the corner is really just a spot to put things and is not usable for a lot else other than maybe some light prep work.
unless you are cooking for say 4-6+ people regularly, the double BBQ box likely won't benefit you much cooking surface wise if you already have a skottle. it would allow for charcoal style cooking/flavor, but you could also do that on a fire with a grill grate (or a takibi set up) or a grill at a camp/picnic area. also i would just use the skottle on its own with its own legs set up near the IGT. I see no point in taking up IGT space if the skottle can stand on its own. flat table space or IGT units for stoves and such are at a premium when outdoors.
if the space allows a 4unit frame would allow you to do one of your cooking surfaces + a sink and cutting board...or 2 of your cooking surfaces. but as mentioned...skottle can stand on its own and then you can have your whole list all at once including a corner and a table for prepping and eating on.