Hey Pete,
Unbeknownst to you I am a big fan of yours or as much as I can be by watching your videos
.
To answer your question as best as I can, not having an eight string Railboard I would say
that the big difference between the two is that the Railboard's neck tapers the same
way a guitar or bass guitar get's wider as it goes toward the body (and as the frets get
more narrow
). Kidding aside this is a big difference especially for a seasoned player.
I guess it would depend on what you want with the critical question being, do you want
your string set up with the bass descending as opposed to ascending. With an eight instrument
I think you would want them descending. Obvious perhaps but crucial non the less.
The "tapping" difference between the two has to do both with the question above and also
that there is a limitation with having only eight strings which I think is why Emmett kicked
it up to 10 and then to twelve. But with eight the tendency is to play more with the right hand
fingertips facing the melody strings (four strings four finger(tips). That would be more Tony Levin style with the instrument more horizontal rather that vertical "Free Hands" style. But why is this? Because with eight strings you need to traverse the fret board up and down the neck moving the hand and arm as opposed to traveling up the scale via the strings with the hand more or less in one place.
All the notes are there either way but with the skill set you have, you are already in the drivers seat with the Free Hands technique.
I would say race car driver. How about this as a nut shell; if you want to play covers get
the 12 string Railboard. But if you want a different way to explore the tapping world
and to invent new music get the NS.
As far as NS vs eight string Railboard
, Both would be cool
. Speaking of cool
Railboards are noticeably "cool" in a colder environment but you probably would not notice
in Phoenix. Thinking that way though, the Railboard might be more stable with temperature change and humidity where you live
.
I hope that helps to answer your questions. The differences are actually pretty complex.
*j*
.~
jRj