A couple of pictures may assist in answering a couple of questions, especially related to nose cap. And what brand/model rifle is this. I'm seeing percussion caps, but a little more info may help.
I am showing my most recent build, somewhat of a nostalgic throwback NOS 54 cal CVA Mountain Rifle build (top). I contrast it with my Don Stith .58 parts set I built 25 years ago and my first build, a CVA Mtn Rifle .50 (USA) from 1977-78.
That looks great. The oil top coat will darken it some.
If you want it lighter, use 400 grit paper or 0000 steel wool and you can take it back a bit. Careful with the paper as you will tend to take more off the high places like around comb and lock. If you do want it super light, us a dilute...
I’ve been working on a NOS CVA Big Bore Mountain Rifle in .54 that I picked up from a member on this forum. Did some staining and nitric acid today. Humidity and temps will be back up this weekend to finish all the hardware browning.
I agree with Pete and can’t stress enough that at least one book on the subject of building the PA long rifle is critical to a successful build. You have chosen decent material to start but these parts sets don’t just fall together (unlike another prominent kit).
Agree with others that a loose fitting #12 tap will clean the threads without risk of recutting you cylinder.
Here is is a source for 12-32 tap. Best be sitting down when you see the price, though:
https://www.mscdirect.com/product/details/74838681