We did tip. Our guide made a comment at some point during our first day how a large portion of his salary was undocumented cash and asked me as a Tax Consultant what his exposure and liabilities were if he were ever to get audited.

We tipped him around 12% of our total fee.

There was no additional costs except for meals. The guide did not allow us to buy him any meals or drinks as he told us that "The Mouse" paid for all his meals and snacks during his time with guests.

I think splitting it between 2 or 3 families would be a great idea and honestly a great use of his time. A perfect example of this was when we went to Hollywood studios and he got my wife and daughters VIP seating for the Beauty and the Beast show and then got son and I inline for the Tower of Terror, then put us in the fast pass line for Toy Story and then took my wife and daughter into the line for Rock n Roller Coaster where we met up with them and picked up my youngest daughter. All in 45 minutes.

Also I really can't express how helpful our VIP Concierge was for us a first time visitor. I can honestly say that if you decide on a "last minute" trip say with less than 2 months to travel date the VIP Service would be great for squeezing you into restaurants and other activities. There is a 4 hour minimum that you have to meet in order to use the service.

I think a great use of the service would be if you were staying on property and had the guide pick you up at your hotel and take you in the back of the park you were going to start with at the park opening time. While they aren't supposed to let you into the park before it opens I'm sure they would be happy to have you in the back parking lot at 8 AM and helping you to be the first on a few of the rides that didn't have fast pass.