Sunnah I'tikaaf

Q: I have a question about i'tikaf. If we start itikaf on the night of the 21st there is a risk that we only complete nine nights (if Ramadan turns out to be 29 days). Will the sunnah still be fulfilled in this case? Or should we start the itikaf at the night of the 20th in order to make sure that we do at least 10 nights?

Changing one's clothes during I'tikaaf

Q: I understand that one is allowed to change his clothes during Itikaf. In the Haram Shareef at Makkah and Madinah since there is no privacy, is it ok if one changes his clothes in the toilet when one goes to attend nature's call? Of course care is taken that one does not leave the Haram only for changing the clothes but does it when it is unavoidable to leave to fulfil the need to go to the toilet to relieve oneself.