Min/Max lav rough in height?

Only thing I can find is that tail piece can't be >24" and that usually drain is 18-22" above the subfloor. I am using Kohler K-2314 sinks which are top mounted and have the drain opening 4" below the top rim. How high can I place the rough in so that I decrease the tail piece?

The only thing you don't want to do is have the inlet in the wall too high, as water doesn't flow uphill well. Best thing to do is to take the faucet you have and install the tailpiece to see what the actual depth is. Keep in mind that the vanity might get changed, and if you don't have a little leaway (i.e., want a deeper sink), you'll need to tear up a lot more if you make it as high as possible right now.

The 'recommended' height won't work always. Some people are using 36" tall cabinets in the bathroom, some 30, or 32, or any custom height, so an average might be really tight or possibly too high, depending on what you select.

Why the need for a short tailpiece¿

It's not a matter of a some extra short tail, just that the standard length of the drain is like 9", and in my case half of it is above the counter. That means p trap will connect at say 28" above the floor, and go into the wall at like 26". I just wanted to make sure I don't need to meet some code by having the rough in at a specific height and therefore having to extend the lav drain.

So it's already roughed in and you want to be sure that it's going to work... I think if you are at the rough in stage getting it to that 16"-20" height would be your best option. Weird things happen when you get the drain too high. Reversing the p-trap to accomodate extra height almost always guarantees a leak. (This is one way to get the trap to work, if it doesn't make sense it would if you were had finished walls and were under the cabinet trying to tie it all in.)

drain

The 24" maximum drain length is a theoretical one, but there is no reason for you to even approach that. Just make sure the drain opening is not so high that you cannot make the final connection. ANY dimension below that is okay.