Most of them I just gained towards the end of the game in order to 3-pile. The first one I got I bought on turn 10, and then I bought another on turn 12. Those were the only two I bought.
Yes, I think you did well with the develop, given you path you took.
I would've tried to end it with a lot of duchies as well.
See above for my answer on the high # of develops. Yes, clearly my opponent had a sub optimal strategy, and so did mine (albeit less so), not having played games like this that often and being in the level range of 22-24. I'll have to look up that deck cycling article. I'm assuming you'd want to 3-pile on something like Duchies, Islands, and Caravans, or am I off on that assumption? Thanks for the input by the way; Dominion advice from a level 50 is always great and sometimes mind-blowing (see: Herbalist on $11 thread 
)
Actually, I'd have no clue yet on how to end it. I usually only make a plan for ending the game about half way. Before that, it's just some vague idea of "I want options" versus "I want power" or "I want points" or "I want reliability". A deck that I can draw completely with an Ironworks and a Devlop clearly has options (3 pile?) but also it could buy provinces rather reliable. (ironwork Island, goodbye Province, hello new Province).
I'm not sure the deck cycling article has been written. But it goes like this:
Buying a single copy of a few key cards and playing them as much as you can is usually better then buying several of them.
This holds espescially if some of those cards thin out your deck, and some cycling cards are available (of which Apothecary is a great and Alchemist a good example).
If you go for it, use everything you've got to decrease the 'deck cycle'. Buying money is quite bad.
