VERY nice Paul for a first light.
Brendan (Macgyver) is very adept with the tools, surprised he didnt grind you up a new FPL51 objective from some bottle tops and mars bar wrappers while he was at it....
Seems to me to be what looks like noise (even at ISO 200) in the black areas, possibly cleanable with a dark/flat frame....
You are right about the second pic, pop is the word I would use. Lots of details and a very nice bit of framing. Ooooh was the exclamation when I clicked on it.
Very nice work from what seems to be a ripper of a set up. I dont have enough experience to offer you any semi-pro suggestions other than that.
Well done
Cheers
Chris