so what is the best balancing method

Just like anything in this country any more people just do not care and have accountability.

I would stay away from putting liquid in you tires for more reasons than I could list!

Why would Porsche and many European car companies use stick on's???

When done correctly with attention to detail you will not have issues!

Find the place that will do what you want and they will have a customer for life and you will have piece of mind!

At one time I thought it was beneath me, after I earned my master certification. I learned a valuable lesson back then after taking care of customer much like you. Doing an over the top job of any kind for a customer earned you more satisfaction and repeat customers than you could take care of. Mounting and balancing is always given to the rookie but sometimes required an experienced tech to do it best.

Best of luck!!