Goldtips, and every other factory fletched arrow, comes with a slight right offset straight fletch, just a couple degrees. They don't come in helical because helical fletching, though beneficial, will cause fletching contact problems on most non-dropaway rests. Not sure not well helical fletched vanes would fare through a biscuit either, but I've never tried it or seen it done. The slight right offset is better than 0 degree straight fletch at stabilizing arrows, but doesn't cause too many contact problems with launcher style rests.
Helical fletching actually wraps around the arrow shaft and if it were extended would look a lot like the rifling in the barrel of a gun turned inside out. This allows the vanes to have a lot more pitch while keeping the base of the vane in full contact with the shaft. Offset straight fletch is commonly misidentified by those who've never really seen what helical looks like because it does have a small degree of pitch. But if you looked at a straight fletch clamp you'd understand that the vane is still glued on perfectly straight and just canted a little bit, but not so much that the ends of the vane lose contact with the shaft.
I have a recommend the Bitzenburger Dial-O-Fletch. It's a very sturdy and well built jig that, once adjusted for your chosen arrow diameter, never has to be messed with again unless you change arrow diameters. I bought mine with the right helical clamp because I have drop-away rests on both my bow and my wifes. Helical is without a doubt the way to go if your setup will allow it. Otherwise get the straight clamp. I used the 2" Blazer vanes with as much helical as I can get. They work very well. The Bitzenberger allows me to choose the standard 120deg 3-fletch (my preference), 90deg 4-fletch, and an oddball 75-105deg four fletch (must be a finger shooting thing?
). It's a good unit, but it is the most expensive single-arrow jig out there. I got it because I know it's built to last unlike it's plastic bretheren.
Mike