Definitely Dita Von Teese.
Although in the UK Jess Impiazzi was on Celeb Big Brother a few years back and her videos she did for UK Tickling were mentioned in the papers here.
1. Off camera tickling to enhance the reactions. RealTickling and Tickle Central were bad for it. Close up shot of foot tickling but you could tell by the reactions that the camera guy would be tickling them out of shot to make it seem like their feet were more ticklish than they were.
2. When...
I'm also in the less restraint camp which seems to be a minority opinion
The scrambling to get away from the tickles is part of the enjoyment for me, it also feels more natural and realistic too.
Seeing a girl completely immobilised doesn't do anything for me and I second what Frankied said...