score:4
If you have data on your phone, I highly recommend the trenit app for android or iOS. It gives you the train times in real-time updated after every station. Usually it tells you the platform but doesn't seem to be giving that for Saronno at the moment. The app is showing the train tomorrow as the 329 at 10:16 rather than the 325. If you miss it there's one just 8 minutes later.
Saronno station isn't very large and from the information on that page it looks like you go to MXP from platform 5/6.
Upvote:0
Turned out to be platform 6.
Going in the other direction, the train to Como Lago from Saronno leaves from platform 2.