From water to weigh in!

I figured this would be a good place to ask this question with all of the Pymatuning walleye guys on here.  I, too, have fished that lake for almost fifty years for walleye and crappie.
My question is what is the best way to keep walleyes  alive?  I have caught them and chucked them on ice, or let them ride it  out in  the live well, but I'm thinking about doing a variety of tournaments this year now that I have time, and I know that eyes are not the easiest fish to keep alive.
I've heard ice in the livewell, oxygenators, chemicals..... What do you guys use???
Thanks for the help