Hello (lengthy response matching OP)
I went for the fiance visa as well, because it gave us time to adjust to the idea of marriage, made it feel less forced and more like something we were giving ourselves time to decide upon, rather than solely a means to an end. Yes, it sucks not working, psychologically and financially. However, aren't fiancees allowed to take classes (someone please correct me if I'm wrong!!!)?
If you can prove you intend to marry and have a relationship with ongoing contact (phone bills/email screenshots are fine), there is no minimum number of visits before they see your relationship as genuine (at least, for Americans that is). Provided you can prove you have a place to live (ie tenancy agreement or mortgage, permission from the landlord or owner for you to live there if the place isn't his) and HE can show previous bank statements, you should be alright.
It is his job in the UK & his bank account that they will be focusing on, and your employment will only be significant in a)helping you have more money to show for the application, and b) proving that you will be eventually employable in the UK. It is favorable for you to have been recently employed at time of app, but not necessary. I wasn't. Also, don't worry too much about the details of your employment. Including a copy of your degree, CV and/or employer references, paystubs/contract from past employment, etc will be more than enough to show what you're capable of earning.
Anyway, that said, spousal visas are a lot easier as far as accompanying evidence goes-- there is less ECO scrutiny on your financial situation because the assumption is you'll be working, and there is no need to prove the relationship.
If you decide to visit before you apply for the visa, you should be fine. Obviously, the longer you intend to stay, the more you have to fight to prove you are a genuine visitor. You were there for less than a month & returned home when you said you would, and as long as you can show you have a return ticket, proof of funds, ties to the US, and are honest about your relationship, all of those things would be in your favor.
A visit of a week or two when you still have a job to go back to will be easier than a month or two with no job at home. Also keep in mind that it will be easier coming in as a visitor with an imminent US wedding than with a future UK wedding. In fact, trying the latter will probably get you bounced because technically you should have a fiance visa.
After all this advice, though, the best thing I think is to just go with your gut. If it's telling you you have enough paperwork to show at the border, and you know how to present yourself, what to say (ie explaining that he is visiting YOU next, and you are taking a couple weeks off before your next job starts, etc) and what not to, then you could be ok with a longer visit.
The forum is good for learning the rules and keeping as informed as possible about your different options, but in the end you can't let it all scare you because then it becomes a self-fulfilling prophecy. For every horror story posted on the forum, I'm sure there are many more success stories that we never hear about.
Good luck!
Di