You're not going to hit 100 notches without a major lifestyle shift. Your life has to be about getting laid, at least for a few years, to do serious numbers. There's just no getting around that. You could do it with day game, night game, whatever... but your life must revolve around it.
Re: apps, if you have One Date, take a look at the bonus book by Alexander Abraham in there. It has his complete system for killing it off apps, and is as good as anything out there.
Re: not getting dates from nightclubs, think about it like this: if you want a woman you met at a nightclub to meet up with you some other time, you need something special going on. Either you need to really strike her as a possible boyfriend candidate, or she has to find you sexy enough to want to meet up and potentially sleep with. If you didn't impress her as very sexy or a potential boyfriend, you're just another club rando she won't meet up with after.
Hotels, sure, ask about their place first. Or better yet, feel out their logistics. You should have a decent idea if the girl's place is a viable option before you even ask; just check her logistics during the conversation. I suggest you pay the first 10-15 times with new girls; after that, once you've got a pattern down and you know you can pull it off, you can experiment with getting girls to pitch in or pay outright themselves instead. As for them feeling slutty, like any pull: just keep the conversation going, keep it light, and keep the pressure off.
Yes, I still recommend not paying for dates. Unless you are clearly the distinguished older gentleman. Dress well, be smooth, and don't get in weird situations where you've boxed yourself in and have to pay or look stingy, and you're fine.
Re: flakes, yeah, I could possibly do another article on flakes. Let me have a think on it.
Re: being a hard case, I don't know man. There's a distinct minority of guys who study game, do their best to apply it, and never make it work that well. Off the top of my head I can think of four different guys I've seen, you being one of them. One's a friend I have worked with a lot over the years, and while we've improved his results, to the point where he can get the women he wants now, he still can't hold onto them in a relationship. And it is just the weirdest thing and I can't figure out why it is happening to him and neither can he or anyone else. I'm sure if I spent a week with a guy like this I could figure it out, and it's almost always some selection of social cues he's missing or basic things he's doing wrong. But the guy himself doesn't know, and he can't tell you, and it's just impossible to figure out over text. You should be getting the guys you've seen do better to give you their critiques of why you aren't succeeding. Better still, ask them to go out with you over the course of a month and keep an eye out for what you are doing wrong, and at the end of the month tell you what you're getting wrong. If you can get a few guys to do this, you'll get some actionable feedback.