How much should I open to in live 1/2

I think you can vary from casino to casino and game to game. You are trying to find a size that is effective at getting you head's up the vast majority of the time. Obviously, theory dictates that you adjust your opening ranges depending on the size you use, but it probably doesn't make a huge difference at live $1-$2 as long as you maintain a decent baseline range.

At my home casino, I usually go $10 +$2 for every limper, but if I am in a game where everyone limp-calls my iso size becomes $15 over a single limp. This is pretty standard where I play, but I have played in places where the standard open-sizes are smaller (I saw a lot of $7 opens in Las Vegas) and in places where opens are bigger (people looked at me like I was an idiot for opening to anything less than $15 in Texas).

I also always add an extra BB when iso-raising from the blinds, but I think that is pretty standard.

I think the goal is to bet the amount that gets you HU the most often. Lowstakes players tend to be considerably worse in HU pots than multiway, and it also lets you size up as much as possible to extract max value from your range and nut advantage.

This is going to be V dependent, and although a simple preflop heuristic is a good starting point, if you find yourself going 4+ ways regularly you should size up, and if it folds thru regularly you should size down.

My general sizing is EP/MP i go $15 +$1 per limper and LP i go $12 for no limpers, then $15 for first limper, then +$1 per limper after that (seems like if you go+3 per limper you just take it down on 2+, although not an awful outcome, not ideal)

But you also need to consider the specific V tendencies. My least favorite V to be directly OOP to is the ones who will fold if it folds to them and call if it calls to them, they just refuse to play HU with me and also tag along and keep me from playing HU vs others.

Also it does not matter what standard sizing is, you dont want to emulate the fish you are beating, and ive played in plenty of places where the standard size is $7, and everyone is used to never folding their limp, so they also dont have the discipline to fold it to my larger sizing, to a point where i keep sizing up to try and get HU and get to a point where im raising to $20-25.

Check out this thread from the best of links for an exhaustive discussion of the issue. If you still have questions, feel frr to bump that thread with them.