There no "right" choice of how many starters you need, but the decision is influenced by how often you can change your lineups, whether you're required to use a certain minimum/ maximum number of starters or relievers, and above all, what your league's games and/or innings limit is.
How your pitching shapes up depends also on how many teams there are in your league, but even if it's only ten, your guys look pretty good. The Big Unit alone will practically guarantee you'll climb out of the pitching cellar very soon. Glavine and Radke are solid, I like Padilla (even though he'll go through some rough spots), Ishii is the big unknown factor (see the Ishii Watch thread). I'm not too high on Castillo, but he's a serviceable 5th starter. I also don't like both Mays and Miller as much as most fantasy folks do, but that's just my minority opinion. Of the two, I like Miller more, if only because Mays might miss a lot of time.
Anderson and Graves are both very valuable - if you can pick them up, you won't regret it.
Of Romero, Dotel and F-Rod, I'd normally go with F-Rod, but since you have Wagner, who is struggling, Dotel sounds better: solid stats plus insurance.
Anyway, let us know your league settings. In most scenarios, though, this looks like at least an average pitching staff, and probably a good deal more than that.
I have 6 starters and still am first in saves, so I guess if your closers are good enough you can have more starting pitchers. However, the total innings thing might be a problem, if you have one. I am currently ahead of mine.
10 team league(CNNSI). At least 900 innings and 3950 at bats. Minimum 5 pitchers active. Means SP right?
Duckworth, Clement, Weaver, Wolf, Lohse, R.Reed, Pavano (slim pickings)
Which one is worthy of Castillo's spot?
WHen or how many starts b4 jump on a hot pitcher? Case in point, missed out on O.Perez bc reluctant to grab him.
Risky but think I'll keep Ishii (pitcher's park and a lefty) for now. Division hasn't hit him well, YET.
Thinking about Pineiro (pitcher's park and good K's)as RP to keep WHIP/ERA down. Possible he'll be SP like last year(he was good last year)??
I'm also liking Romero, Hasegawa, or F. Rod since Dotel's mechanics has been off.
I'm thinking the relievers are a better option than Graves and Anderson (less save opportunity bc of weak team save for CIN's hot streak) bc pitch more often (more opportunity). Am I wrong to think this?
Two more questions: do you mean you have no innings maximum in your league? Also, can you change your pitchers daily?
Anyway, I like the guys you listed pretty much in the order you gave, with Duckworth just a fraction above Clement. Not bad options to have, on the whole.
Don't worry about Pineiro yet; wait and see what happens over the next couple weeks.
If you're looking for a middle reliever, I'd put F.Rodriguez at the top of your want list.
Graves and Anderson are better options than any reliever, though, since you need saves. Don't worry about opportunities; in general, a closer on a weak team will have about as many save chances as a top team's closer (the rationale being that the team will win less, but of those wins less will be blow-outs).
And I don't think anyone can give you a tried-and-true formula for how soon to jump on a hot pitcher. It's more eye-of-newt than scientific projecting. All you can do is compile as much information as possible, including:
Who has he pitched against during his hot streak? Beating the Yanks in the Bronx sounds better than achieving the same stats against the O's.
What was his k/bb ratio? Has he improved this significantly recently?
If he's a rookie, how high were the scouts on him?
Has a previously average pitcher made any adjustments (learning a new pitch, for instance) that would explain his improvement?
To give some examples (that reflect my own biases), I'll happily jump on the Fogg bandwagon now, since I liked his potential in the minors and like the situation he's in. On the other hand, even though Byrd's stats have been amazing so far, I can't figure out why he's improved so much, and wouldn't take a flyer on him yet. Kenny Rogers? I'm not buying it. He's the same pitcher he always was. Padilla? Worth a shot. Pedro Astacio? Go get him...