Haven't heard more than the first two videos so far. I like them, but the genre into which Gideon plays is no surprise to me, as we have mailed privately for reasons to be disclosed later on. Along the road I got the link for the site of this wonderful folk-funk group.
Gideon's helicon is built on the pattern of a Herkulesophone (German spelling of Hercules):
herkules.jpg
The text loaned from
http://www.tuba.org.ru/english.htm" target="_blank" target="_blank" target="_blank" target="_blank" target="_blank" target="_blank
says:
Schediwa "Herkulesophone"
Around 1882 Josef Josefovich Schediwa (1853-1915), who had worked for Cerveny, founded his own factory in Odessa, producing, among other tubas and basses, a variation on the helicon that he christened the "Herkulesophone". He published a "Catalogue for the production and ordering of metal wind instruments" with many, many designs, schemes, charts and diagrams.
The characteristic thing about this variant is, that the ones in F have all but the bell stack in front of the player. The ones in BBb have the equivalent of the 3rd or 4th branch behind the player's back also. The air runs counterclockwise through that slim branch, which is rare for circlophoniums.
These photos (if I am not mistaking something) show front and back of Gideon's instrument:
Front.jpg
Back.jpg
Klaus Smedegaard Bjerre
PS to Gideon: I have been on the phone with PP a couple of times and thinks should work out well.