The luggage question is difficult because there are so many variables, and it’s different for everyone. Jim splits his carry-on items into two bags so even on smaller aircraft, one bag can go in the overhead while the second bag goes under the seat. He brings one camera bag that holds most of the camera gear, along with a daypack which holds his laptop, an extra camera body, and miscellaneous things.
For his checked luggage, Jim uses a 22″ roller suitcase. This works for Jim, but keep in mind, he’s not hauling back souvenirs. You may want to bring a larger bag, but be mindful of your destination. If the tour will have regional flights on smaller planes, there will surely be different restrictions on weight and carry-on sizes. It’s also important to keep in mind that you’ll be responsible for your luggage when travelling through airports if there are any regional flights on your tours and while some properties will have bellboys or other staff to help you, not all will, so you should be able to handle your own bags.