if I had a guitar made by Crimson guitars, especially a custom one made by Ben Crowe, I would never touch another guitar again, you are a lucky man! Yes PRS do have a good reputation, even the cheaper ones are pretty good.
you can only learn through experience, it's always worth hiring someone for mastering in my opinion, even if you can master your own stuff, it's almost impossible to be objective because by default you will have some form of emotional connection to your own music.
mastering is simply the final process, you should not be mastering samples just so they are loud enough, if it was me and I was sent 'mastered' samples, I would turn down the work or request you send me the uncompressed version.
that spectromiter is only useful when you can't find a certain problem frequency, that's how I use it mostly, don't forget your ears are the most important decider in the end.
it's some kind of grounding issue, that could potentially be fatal, you need to open it up and see what's going on inside, it wouldn't surprise me if the circuit is not grounded, take it to someone that knows what they are doing, it can be dangerous.
I don't know him personally no, he has a company in the USA called Acoustic Fields, I think it's Acoustic Foam & Low Frequency Sound Absorption Specialists, even though he is in the USA, he helped me out with my room, I bought DIY plans from him and plan to build his bass trap design and...
you don't have to credit anyone if you are writing the music and it's original, you can use sounds as much as you want, even if you made £100,000,000 and had a multi national #1 hit that lasted 40 weeks and sold 10,000,000 copies a nano second, you are still covered.
you've got some good ideas here, I'll be keen to see the end result! I like the idea of concrete blocks, you seem to know what you are doing here, can you post photos of the different stages of constuction? that would be amazing.
I fade on a lot of tracks, mostly the lead vocal, but at the final stages of a mix, I fade everything in different parts of the song, it's better than using compression.