One of the biggest labs here in Washington State doesn't even have large ingots. They do everyhting with two ingots. Really scary. I know this for fact, because I order my ingots through them ( get a better price and no shipping) When I need large ingots, I have to order them from Ivoclar direct. Just because you can do it ( physically) doesn't mean it is a good idea. Microcsopically you will see a seam and you create an fraction line.
One thing please keep in mind. If you use a large ingot, do not try to press 2 grams of wax. It does not work. the large ingot is the size of two small ones. When you can press 0.75 gram per small ingot you should be only be able to press 1.5g with a large ingot. I had several miss presses due to lack of material. I dialed it down to 1.8 as an absolute maximum amount. This leaves a paper thin button. Also if you push the wax weight to the limit, weigh the ingots. There is quite a discrepancy in the weight of individual ingots.