Heya, Colombo
Sorry, I didn't have much of a chance to reply over the weekend, but it looks like you enjoyed a very edifying weekend!
From what you're describing, you've done a marvellous job of dissecting Dark Road; the detail you've managed to glean from listening to the CD is far beyond what most people would hear or notice, and this ability is going to serve you well.
A little tip as regards working out chord 'flavours': I had no formal training, so all the chords in my vocabulary, certainly in my earlier years, were worked out by trail-and-error. Sometimes I'd come across a chord that didn't have the 'colour' of those being tried from the root note I'd ascertained it to have. What I'd do at this point would be to sing the 'alien' note and then try to re-voice the chord with it included. That's pretty much how I learnt all of the chords I know. This method also has a benefit in exercising your Musical Ear further, also allowing you to recognise the same voicings more readily when you hear them in other songs.
You're absolutely right about there being more that one rhythm guitar — there may be more than five…or ten (you'll need to ask Richard about this!), all judiciously mixed and adding a supporting-role to the depth of the sound. The higher inversions of the chords will be played either with barre-chords or by using a capo (one of my favourite tricks). If you have one, put it at the 2nd fret; now, while jamming along with the track, in place of the A play a G; replace F*m with Em; Bm with Am; and E with D. This isn't the only place on the neck where you can use this technique, either, and combining this with open-stringed chords, playing major chords against major 7th chords, and myriad other combinations, you can add a real wide-screen depth to a recording.
I wasn't familiar with your guitar, so I did a little Google — what a LOVELY instrument! And with the alnico pickups, too: wonderful! I also looked at the controls for the Vyper: seeing as it's a 'modelling' amp, being able to make a suggestion for settings is a little more vague, given each manufacturer's 'take' on what they 'think' a piece of vintage kit 'should' sound like. However, if you pick an old Fender-type setting (Dlx?), put the pre to around 1 o'clock, the bass to 3 o'clock, mid to 12 o'clock, and the treble to 2 o'clock, you should be in the right ball-park. Don't forget the reverb! On the guitar, select both pickups, set the volume on the bridge pickup to full and 'bleed' in the neck pickup just so you can hear it adding some 'weight'. One more thing: put the amp facing out of a corner; you'll achieve a more natural, pronounced bass without over-stressing the amp and speaker.
Having said all this, it's worth remembering that the original tones that Richard's basing his on were created on amps that only had a volume and tone control, and reverb was added by putting the amp at one end of a room and a microphone at the other. We're so lucky, these days…or are we?
Heavy picks: yes, I always use one of around a millimetre in thickness, usually made from nylon. The only time I use a light pick is when I specifically want the sound of one on an acoustic guitar. Other than that, I find that by changing how I hold the pick, I can alter its 'perceived weight'. The benefit of a thick plectrum is that you're not waiting that millisecond-or-two for it to finish flexing and pass over the string; this gives your playing an immediacy, and offers greater control of dynamics.
BUT, ALL of these things are down to personal preference — do it how YOU want to
I hope these things help a little. Sorry if this message seems a little matter-of-fact — I wanted to get as much information across as my lame typing-skills and time would allow!
By the way, DO record your vocals!
Have fun
Michael
PS: I'm sure we haven't gone off topic: this is all guitar related!