45 adapters

I recently had the opportunity to acquire cheap a number of the "old style" 45's with the BIG hole! Some of these are DJ promo copies that have never been played. They sound pretty darn good on my 'Not. I am using a few of the old plastic inserts that I had lying around to fit my spindle. Can anyone recommend a 45 adapter that would be better to use that the plastic inserts without going totally nuts? Or, is this about as good as it gets?