"...I clean and degrease with casey's cleaner/degreaser then polish to bright with 400 grit wet/dry paper..."
Unless you just printed the sequence switched, try polishing first,,then doing the degreasing.
Actually, if you don't have a particularly dirty & oily piece of metal, draw filing, polishing with grit cloth will give you a nice surface to apply the rust blue soln directly to especially with Laurel Mtn.
I wouldn't go much higher than 280 or 320 for the first attempts at rust bluing. The higher gloss will just get matted down during the process anyway. Later on you'll get the hang of being able to adjust the times, temp, and humidity to keep a high gloss under a rust blue.
The copper streaks are common with LMF blue soln.
If you over lap the soln while applying or rub it in while applying you'll usually get a copper plated effect that will still be there after boiling.
If the metal is warm, the soln will plate out while you are applying it too.
If it appears after the boiling process, it's usually from old blue not being completely removed in spots. Sometimes the newly applyed LMF will reblue nicely over old bluing,,sometimes you get the rust/copper areas appearing where old blue remains. A light polishing over the areas will usually take care of it giving the LMF a chance to bite into the steel underneath.
Old rust blue can be tough, with dried, hardened oil in the matted pores of the steel not allowing the new soln to get ahold.
A first coat of quick rust at a somewhat high surface heat on the steel can be helpful to form a base for the LMF slow rust coating to follow.
Etching the surface does the same thing. Either with weak acid on the hot steel from the boiling water tank or a very weak ferric chloride dip (less than 5%), just enough to give the rust blue soln a surface to bite into.
The latter is also used to etch for damascus pattern.