One big thing to remember when installing bands is,get the band and drum clean.Not wire brush clean,not wire wheel clean.Clean as in zero paint,rust,scratches,burrs,nothing.just a little paint dot will force it out of true.I use to work for an old fellow that did hundreds of them.He would put the drum in his brake lathe and run over the OUTSIDE of it.You would be shocked at the amounts of rust and mung that build up on the outside,and the wire wheel leaves behind.Also,check to see if the band has a weld seam.Make sure that is 100% flat on the inside.I put a set on some thin,but evenly worn drums.I scraped the outside in the lathe,heated the bands red,and dropped them on.They bottomed out with a clink,and stayed there.I never even had to true them.