Have you ever finished before??
I ask because TV white is not a colour, but a process.
And darkbacks are such a range of colours that there is not one answer.
Plus you are trying to get a colour when the originals were created by mixing tints and pigments into clear for the most part. Add more into the clear and spray one intense coat and you get a different result to the same amount of tint but over many coats.
Its not like painting a car where you ask for 'x' colour and you know what you are getting.
You seal the guitar with either shellac or a thin coat of vinyl sanding sealer. Go thin. At this point, you want the guitar's grain to show.
Two coats of color, again a bit on the thin side. You still want that grain.
Now you fill the grain with your filler of choice. Use a dark filler. You do this over the color coat, wiping the filler on with the direction of the grain. Wipe off before it's completely dry at a 45 degree angle to the grain, as to keep most of the filler in the grain. Wiping it off with the grain can pull the filler out.
Clean this very well, but not to the point that you are rubbing through the color coat.
Now you can proceed with clear coats to cover the color coat and the grain filler.
Far as "dark back goldtop", I'm not sure what you mean.
Couple of tips... brushing out the grain with a fine wire brush before the first light paint coat helps accentuate the grain. Also after the contrasting grain fill, one or two final light passes of base paint thinned and near-translucent helps blend it all together before clearing.