Regarding slot size on Quinte... In the 2005/2006 version of the regs, it states that you may keep zero walleye between 19"and 25" and only 1 over 25" long. Right before opening day in 2005, they changed the regs to eliminate the slot size restrictions. The regs were ammended to allow anglers to keep 1 fish over 25". So, as of spring 2005 you are allowed to keep 4 fish with only 1 being over 25" long. The 2007 regulations are behind schedule and anglers have been told to abide by the 2005/2006 regs... Including ammendmants. In a nutshell, the rules are the same as last year.
But... If you are at all unsure, don't take my word for it. Go to the MNR website and look it up for yourself.
Here's a link to the MNR's fishing regulations. I can't find a link to the Quinte ammendmant. I'm sure it's there, you just gotta do some searching.
http://www.mnr.gov.on.ca/MNR/pubs/pubmenu.html#fish