Guys I feel your frustration having done it myself.

Suggestion #1: Make sure they give you the lbs# value of how out of balance and or round they are - for each tire.
There's a ton of threads on here about how this works. But roughly it simulates pressure on the tire to simulate how its going to roll on the road. When the wheel is out of balance its going to exert extra pressure at a certain point in the rotation which can be measured in LBS.
Suggestion #1: same as #1 -Again make sure they give you that LBS value for each wheel before accepting the wheels as balanced.

Many places will say under 25lbs is acceptable. But some will still feel vibes at 25lbs. Under 20lbs is better, under 15lbs is fantastic, under 10lbs is Cadillac luxury smooth.

As I posted in the other thread "another vibration issue", my last set KO's sucked big time, I spent about 20 hours at DT over 5 different trips, even brought my own beach chair to sit outside. Appointment #3 they popped the bead and spun the tires on the rims. Eventually they replaced a tire at appointment #4 and another at appointment #5. Like many here after being there for 2 hours I don't have time to stick around and had to schedule another appointment. Then when you think its fixed you go in for a rotation and the worst tires they stuck on the back since you wont feel it there end up on the front and boom your problem is back.