Importance of a second opinion and a question on Sinemet/ new here

I am still going through the diagnostic process for PD. The Veteran's Hospital neurologist thought that 90% of other Docs would be diagnosing me with PD but she wanted to look into dystonia first. Since I still have medical insurance also I decided to get a second opinion. The other movement disorder doc stated that he wanted to see the results of the MRI I just had and also the sleep study the VA has scheduled for next week. He did not see where the dystonia fit in but did put me on Sinemet/ 1 tab three times a day. I was doubtful on the first diagnosis and really appreciated the second opinion. He said that PD was on the top of the list for me. I depressed the crap out of me (and still does), but I feel much better knowing that another doc felt the same way on what I have. BTW my VA doc had no problem with the second opinion and stated it was a good thing. She had put me on beclofen and I asked the second doc about that. He said that many with pd also have dystonia symptoms also (lucky me).

I do have a question related to the Sinemet. How long do I need to wait till I see some results of the drug and what will they look/feel like?