Here is pretty basically what I have lived by and I have yet to me disappointed.
Curing Times
“Curing times vary with meat, but generally overnight to 2-3 days for chickens and turkeys, 8-10 days buckboard bacon, 10-14 days belly bacon, pork shoulder, whole butts, 3-4 weeks whole hams, 10-20 days corned beef (fresh beef roasts, briskets, rolled rib roasts, etc.) If whole muscle is more than 2" thick, then inject so it can cure i/o as well as o/i, and/or in and around bone structures, etc.”
I have seen some try a vacuum wet cure but really seems best used for thinner sliced meats like steaks & Chops.
Any time you have meat over 2" thick OR a bone in, I always inject. It is like a simple and easy guarantee. Why wouldn't you. I visualize a 2" grid pattern on the meat and hit it about as close as I can to square.
You have to realize that within a larger cut of meat there are different layers and densities of meat. You have fats, tendons, cartilage, and you want to transverse thru all of them.
OK, heres a picture of a good example of a piece of thick uninjected meat (which was intentional BTW).
See what I am talking about towards layers and densities?
Its just too easy to take the time to inject to ensure a quality cured meat not to do it.
But the bottom line is, whatever works for you is how to do it. We will all agree here that there are lots of ways to achieve the same end. We basically want to suggest safety concerns as being the only exact science.
I have no problem extending the cure past the due dates, but pulling early is like Russian roulette.