Hard to say, re the 1/8" bubble. I would think it would be OK, but it probably depends on the level. My digital level showed my pole off by about that much, and it was still reading like 89.8 deg instead of 90.0, which shouldn't matter much. Tilt to the south doesn't matter at all, because that will be taken care of with the elevation adjustment, but tilts to the east or west are more troublesome. Your pole will probably tilt the most however, when it's aiming near the east or west horizon.
You want to see tilt though.... back in the 80s when a friend and I both bought dishes, he got his first, and went to a hardware store and got sched 40 pipe, and planted it in concrete. I went over to help install the dish, and it turned out that PVC pipe can also be called sched 40, and that's what they gave him, instead of steel. We put the dish up anyway, thinking that we could anchor it with guy wires, but as the motor turned, that dish tilted 4 or 5 inches in whatever direction the dish was aimed. We eventually planted a new steel pole right next to the PVC one, and moved the dish over.
But that was funny to see that PVC pole staggering around.