Wel, my experience's not very good regarding my attempt but good in sense of getting knoledge and info.

I've just learnt to do the syllabus completely (of everything), don't look at past papers to see that can you leave something. As paper pattern is changing every year.

And one should be really careful in choosing subjects and should look at datesheet before choosing subjects. As it's difficult for some people like me to take papers on consecutive days. As I'd to face problem in IP history and Physics.
Very tiring routine of papers.

But what I can say about my experience regarding optionals is this that I'm totally satisfied with my choice.

I can't express myself well, so if your question is unanswered then ask me.