Let's start with an assumption of mine: You have been playing nongay characters, which means you led your personal life with a sense of freedom while being able to act convincingly on stage. I don't think your question is really about your acting ability; it's about the effect on your life if your integrity is compromised. You know what it's like to have a successful career and not have to live a lie. Remember, coming out is primarily an ethical act about honesty. You are really questioning what going back into the closet will do to you.
This reminds me of the recent play "The Little Dog Laughed," in which an actor's agent pushes him not to publicly reveal his sexuality. So who is advising you? Is it your New York agent? New Hollywood management? Who is saying what? Are you getting pressure from friends and family about not going back into the closet? What is everyone's motivation for advising you? Answering these questions will help you to decide if the advice is well-judged.
Now, I'm assuming no one is telling you to change your sexual orientation, which is not possible. What they want is for you to put on a show of being heterosexual. So how far can you take this show without feeling you are compromising yourself? Can you simply decline to discuss your personal life with the press? Are you being asked to publicly deny you are gay? Does it mean never appearing in public with another man as a date? Never living with another man? Are you being asked to become engaged to and/or marry a woman? Where do you draw the line beyond which you will not go?
For many years, the press about Hollywood stars successfully created the illusion of heterosexuality while the reality of their lives was very different. Today, more and more movie and television actors are being public about being gay without it adversely affecting their careers. Still, there has yet to be an out actor who plays romantic leading-man roles. Honesty still has its price.
You cannot change your past life in New York and your positive experience of it. So how much deception can you comfortably live with? There probably isn't a definitive answer to that, but to reach any decision you will first have to be very clear as to what is actually being asked of you by Hollywood. Ultimately, it's your values that will tell you what you will and will not do. Consider it an ongoing process. We are all constantly making decisions about the priorities in our lives and what it takes to live comfortably with ourselves. Be very clear as to what questions you are asking yourself. Then be totally honest with yourself, and you will make the right decision for your life at that time.