Follow up on my wheel ?

I had posted a couple of days ago about my 18x8.5 Foose speedster wheels with the 20mm offset hitting my fenders when i drop the truck down. The adapters stick the wheels out to far but what about running a 1/4 spacer. Alocal tire shop loaned me a cheap one to try it to see if it would work and the 1/4 inch looks like it will work, close to the tie rods but not hitting.Give me the do and don't of spacers.Thanks to everyone who tried to help me also.