I have ballbearings in all the roadwheels and idlerwheels on my HL Tiger 1. I bought a set 8x4x3 bb's on ebay.
Then I milled out space in the wheels to accept the bearing's 2x in each roadwheel and 3x in the idlers. Quite a bit of work, but now the wheels got no play. The wheels are Asiatam's late metal roadwheels. But there are to much freeplay in the suspensionarms on the Asiatam's metal hull. I'm waiting for the Tamiya's suspensionarms to se if that helps.