Much like paypal, google wallet is not sex worker friendly. Several ladies around here have used it, and about half of them still do. The other half have had their GW accounts frozen without notice and are now unable to use it ever again.
In terms of privacy, as of right now, you're most likely fine. If you make a unique email account with only your cam name on display, never link it to any personal stuff, etc., etc., and use it to transfer funds to your personal GW account then withdraw. That's a lot of work, but sure. Risk of chargeback is fairly low. Risk of account closure, however, is very high as mentioned above.
That said, if you're on MGF and take off site payment, MGF will see that in your message history and ban you. They track conversations like crazy. I've heard of ladies getting suspended just for telling someone no to offsite payments. You risk your entire MGF account hardcore if you do it.
Dudes who aren't willing to pay on the site where they found you (here: MGF) are usually scammers who will report you to the site, report you to the payment processor, and try to screw you out of money. Also, $500/month for a few shows per week? He's low balling the fuck out of you. Realistically, even at my absolute flat rate for my best customers, $500 my cut gets them a grand total of 3 hours of skype shows. I guarantee you that dude is going to milk the fuck out of you and waste your time, blackmailing you with potential reports to GW or MGF if you don't give him extra.
In short--DON'T DO IT!