What about the fact that if you raise 3xBB preflop and you get one caller your SPR is about 13 on the flop if you both are 100bb deep. Does this mean you should be opening for more or less then 3xBB preflop?
Setting up a good SPR for your hand type is definitely a consideration when considering preflop raise sizing, but sometimes, the sacrifices we'd have to make in order to give ourselves a comfortable SPR to stack off just aren't worth it. Yes, opening for 3-4 bbs will usually put us in a spot where the SPR is awkward for our hand if we have AK/AQ/TT+, but that's assuming that we're thinking that we should always stack off with an overpair or TP hand. This simply isn't the case. Being cognizant of SPR allows us to make commitment decisions postflop. If we have AA and get called preflop and the flop is T 5 2 rainbow, we don't have to plan to get all-in vs every opponent (and we probably shouldn't). What we should be doing is putting our opponent on a range, figuring out what kinds of hands he'll be willing stack off with, and act accordingly. Against someone whose stack-off range will be T9/TJ/AT/JJ/QQ/KK/TT/55/22 (which we have 75% equity against) I'm happy to stack off. Against a nit who's stacking off with TT/55/22 only, I'm going to be VERY cautious if he calls the flop and raises the turn. Note that if the SPR was 4 or 3 as opposed to 13, the main question wouldn't be "Do I want to get all in?" it'd be "How the **** can I get all the money in hurr?"
Preflop raise-sizing (in my opinion) should be dictated by the strength of your range, and the table dynamic. The stronger your range, the larger your sizing should be (for value). If you have a wide range (either because you're at a nitty table and expect to take it down a TON) or because you like having lots of maneuvering room postflop, you'll want to raise less. At a table that's very passive preflop and very fit/fold postflop, you may want to size larger preflop and smaller postflop. Lots of adjustments can be made, and if we're making them for the right reasons, our winrate will increase.
As per your second set of questions, I'll try and look at some spots (I'll probably be requesting some HHs for review in our last episode) but as always, there are some general questions you should be asking yourself.
If you're going for thin value, ask yourself if your opponent has anything worse that can call, figure out what those hands could be, and size accordingly. If you blast the pot hoping to get called by something weak, chances are, you're burning money.
If you're thinking about bluffing the river with a missed draw, it helps to know what kinds of hands your opponent can call a preflop raise and two postflop bets with that will suddenly want to fold the river. Barring that, someone whose call flop cbet is 60, whose turn call cbet is 70, and whose went to sd is 18%, is a good person to bluff with your missed draw.