I have done both brush and immersion gold plating in my saxophone repair shop. To re-plate a rose gold saxophone bell immersion plating is difficult. It is much easier to "brush plate". Doing it yourself is fun, but it is quite expensive to set up. You need at least a handle with 3 anodes and covers, an electrocleaning solution, an activating solution, 24K hard gold brush plating solution, rose gold brush plating solution, and a DC power supply. I buy my supplies from
Gold Plating Solutions in the state where I live. Their instructions say that rose gold must be plated over a layer of 24K bright gold.
For example:
(3) plating wands, handle, wires, and sleeves about $75
electro cleaning solution, and activator about $30
24K gold brush plating solution $105
Rose Gold brush plating solution $99
DC power supply on Ebay This is the one I use. $68
Total under $400 I found this plating company in your area
King's Gold Plating. You might check with them for a price which may be less than what you could do it for yourself.
You could spend about $400 for a Caswell Plug'N Plate Gold kit, but trust me without electrocleaning, surface prep, and carefully controlled voltage you
will not be happy with the results.
For those curious about the "correct" way to do gold brush plating here is a video from Gold Plating Services. I don't know why the sound doesn't work. You can turn on the closed captions to see what is being said.