Mark,
I visited the factory a couple of eyars ago whilst in Tuscany on holiday. Highly recommend it. It's free and there are two main 'slots' each day. In the morning and again after lunch.
Tis best to find out if the gift shop is going to be closed for any period of time and plan your trip around that. 2 weeks in August is a prime example. Practically the whole country closes for 2 weeks.
I've put a bit of info ( mainly who you need to contact to arrange the free tours) on my website.
Have a look
Here A load of the club members went over a couple of months back. I am sure they'll respond to your post to.
Any probs, just shout.
Guido