My friend,
You are in the very sensitive step! as SINP provide your nomination letter then you have to send your application include nomination letter to CIO and for FSW2014 it is also the same story and If you post both your applications then CIO will work on them within 45 to 60 days and then they will send your application to your local visa office. At the local visa office there will be two different queue for FSW and PNP visas. in the past years PNP queue was very faster than FSW queue but FSW 2013 experience shows us NOW, FSW queue is very fast and some applicants in some visa offices could get their nomination letters within a year and it means FSW now is better than PNP because as you mentioned with FSW visa you are free to stay at any province you want inside Canada.
BUT there is a problem in your case and it is: In both SINP and FSW package you have to send your original IELTS result and because in IELTS general module there is one certificate copy only then how should you send both packages to CIO?
There is another way I can suggest: you must read first carefully the SINP nomination letter to see how much time you can wait before you send your application to CIO (I mean, is there any expiration date for SINP letter?) IF it doesn't have any expiration date then you can keep your nomination letter and send your FSW package first. they will review your package and send it to your local visa office within 60 days and in that step you will be confident that your file is accepted and then you can send an STRONG detailed email to SINP and explain because of their long delay for your nomination you decide to apply in FSW and you want to drop your application with them!
And if there will be any unforeseen problem with your FSW application inside CIO then you can send your SINP package to them after and drop your FSW application then!
I suggest you to think twice before you apply because it is very sensitive decision in your life my friend.