Sorry...but with a RZ, bags that offer quick access, meaning...quick side or...that provides easy access to the gear.
top access, really won't work well with the RZ.
Get a bag that has a full zippered back with adjustable dividers. Take the pack
off your back, lay it on the ground, fully unzip the back, access camera.
Shooting with the RZ's bulk and mass, you sort of give-up anything...quick.