I would not wash a show quilt unless I had to remove water solvable markings. You always run the risk of having a bleeder even if pre-treated.
If you do need to wash it to remove markings, gently agitate with lots of water and colour catchers, spin and CHECK for problems. If everything is good, put in the dryer for a bit and take out while still quite damp. Lay a clean sheet on the carpet and block the quilt out on it. You can use rust proof pins to hold it taut and it should dry almost twinkle free and nice and square.