You need to get one of
these if beef roasts are going to be on the menu. I used to work at a banquet hall/restaurant that ran roast beef for brunches and functions. Our altoshaam cook and hold oven saved our behinds by preserving the meats quality during holding. You can even set it to cook over night and have a roast that is beautifully pink all the way through! There are also models out there that can add wood smoke during the cooking process, if you are into that kind of thing. Look into getting an oven with steam capability as that can greatly reduce shrinkage.
As far as cuts of meats go, avoid anything with a bone in it for a carving station. This leads to waste of both meat and labor. The cut I have used most often was the "Beef Rib, Ribeye" which is boneless. Order it by the NAMP number, 112. To visualize, this cut is where ribeye steaks come from. You can also go with a 109 which is the same as a 112 but it has the bones attached. We used to buy the 109's when we got a good deal, then we cut the ribs off before cooking the roast, and saved the ribs for a special.
For cooking it, we put a seasoned it with a good deal of salt, black pepper, fresh garlic, and rosemary. We used low temp and long time cooking in an altoshaam oven. If you cook it in a regular oven you will need to let the meat rest for at least 1/2 hour, other wise it will lose all it juices at the carving station. However you cook your roast, the goal is the avoid reheats. Reheats are only good for people who like well-done beef.
For turkeys buy large breasts off the bone. It is difficult to get even slices and any good yield from a whole bird. Also less the 10-15% of the population like dark meat. You should also look into brining (or salting/seasoning 24-48 hrs in advance) your birds for added juiciness. If you are buying kosher birds this may have already have been done for you.
Equipment: Do not get the cutting board that has the light attached to it. We had those, and they are impossible to keep clean and sanitary. You'll need a setup that will capture the jus from the roast. The best setups are standalones that have an integrated jus well built in underneath the meat. You'll also need a cook that can keep his knife sharp, and has the skill to cut
thin slices (this takes work). Nothing mangles turkey worse then a dull knife