Quartets were my first set of Klipsch speakers – bought new ~1992.
I would start with ~18” from the wall(s) and tow-in to have the intersection point ~1-2' ahead or behind your sitting position - try various positions to see what you like. You may want to also try them without the stands just for kicks.
In the end I would venture to say that you would upgrade to the Crites Ti tweeter diaphragms and re cap the crossovers as the caps are knocking on 30 years old if still original.
When it comes to capacitors it is a bag of snakes for sure. You will read the gamut of “OEM approved” to higher grade caps. But this much I would say – few people have disliked the quote “new sound” of “aftermarket” caps over the OEM polyester based caps. I'm not passing judgment over any type/brand of caps, just what I have read (and done) over the years.