On my bike, I built a small rack that would slide into the Receiver Hitch on my bike.
that rack holds a small ice chest just barely big enough to contain the inserts, and ice and water.
Over time, I have discovered that you get better performance by soaking the entire vest with the inserts remaining in the pockets. I feel that also helps to prevent punctures of the silicone inserts.
15 minutes will cool it enough for 2 hours, 20 minutes or more will cool it for 2.5 hours of use.
I developed the habit of stopping for fuel at 1.5 to 2 hours of riding.
Jerk off the vest, push it down to the bottom of the ice/water mix.
go take care of my inside chores, come back out and fuel of the bike.
pull the vest out dripping wet, let it quit dripping heavily, and then just put it on. I wear my mesh riding jacket over that.
that wet vest performs 100% better than a dry vest with cold inserts.
I chose the bright lemon/yellow vest, the one on the left side of this page: