So if I decided to volunteer for 16 hours to get badge reimbursement, and gms can get hotel reimbusement how many hours of gaming would I need to do to get hotel reimbursement and vol for 16 hrs or would it just be easier to volunteer for 32 hours?

This is explained in the Event Host Policy; while you CAN split hours between volunteering and GMing, it's not the norm, it's much easier to do one or ther other.

The Event Host Policy does say that you can split between GMing events and volunteering to get reimbursement, but doesn't mention how many player hours of event time equal volunteer hours.  From page 20 of the EHP:

"If your events do not meet the minimum requirement for hotel reimbursement, you can earn additional hours as a general show volunteer. See Volunteer HQ on site or email Volunteers@gencon.com for more information."

i would email them and see how GM player hours would convert to volunteer hours (or vice versa).