How to do good PI cell cycle analysis

Hi,

I'm trying to improve the way our department does cell cycle analysis using PI (we read out on FL3 Lin). Firstly, does anyone have an opinion on how best to synchronise the cell cycle?

Also, on the first couple of attempts I've been involved with, there has been quite a difference in the fluorescence intensity of what I understand are the G1 and G2/M peaks, so much that I can't place gates on a positive control and copy them on to other files. 

Also, FlowJo's cell cycle curve fitting tools seem to throw a wobbley every other file and just won't give me any data?

I'd be really grateful if anyone has any thoughts! Thanks!