Gilles is just acroos the lake from me. A few precisions:
We are not allowed closed circuits here in Switzerland since a 1950 crash in GP France (lots of spectators were killed, it was the Mercedes Silver Arrows).
So the only thing we can do inside the country is mountain racing (for lack of better words). This is what you see in this vid.
We are not short of mountains…

Same championship happens in France in the same region as mine, not short of mountains either !
Think TT racing uphill in the midst of a pine forest and you'll be close.
Extra Titanium reinforced balls are mandatory and also a good life insurance: crashes are often fatal.
I am almost 100% certain that it is Gilles himself you see slicing through the curves there, he often had 309 or 301 as his number.
Gilles is locally known as "the Witchdoctor", he started building TZ frames in the 70's on his own.
He was racing in the circuit races until 86 when a big crash meant he concentrated in the mountain races (even more dangerous?!!?)
He is at least 14 times "King of the Mountain" in 250 and 500 class.
One of his bike (the one you see in action, I think) is a 572 cc, 169 hp and 133 kg wet. He used that in the 600 class. Nowadays 500 = 600cc.
Another bike is 612cc, 146hp for… 126 kg, for competing in the unlimited category.
The 572 had an Rc30 swinger and the 612 had a home-made one.
He manufactures the rest of the bike himself

including frames.
Apart from the crankcases, the motors are all designed and built in-house.
To think that he started in life as a woodworker

You might have been mistaken mentioning ROC, as the bike's are known as RGCs, very close looking names.
I don't think he ever work for ROC, lots of other strange jobs (theater technician amongst other).
Sadly, during the last race of 2007, he crashed hideously and was almost declared dead (his heart stopped). He spent a year in coma, massive brain bruises.
Last news we had in may last year, was that he started talking again, although he thinks he only won 8 titles!
So very slow recovery.
When you ask him what he is dreaming about: 2 words: "victory" and "moto"…