At best the Gilles drop 10mm from standard height by their claims, but when I compare mine to standard I don't think they are even that. On the plus side you can also move them further back so that helps straighten your knees, but at the expense of putting weight on your wrist.
Ther are various companies that do dogleg drop links that allow you to fit your pegs up to 1" lower, I am sure M&p or demon Tweeks sell them
They look very similar to MFW adjustable footrests that M&P used to sell for the Storm, although now it looks like you have to buy them in separate parts at M&P.
LotusSevenMan fitted a pair of MFW's (IIRC German manufactured) to his Storm a long time ago, he found they were a big improvement for his well over 6ft height. As I remember he had to heat up his brake pedal and bend it to suit his new foot position.
As for grinding your feet out, that will all depend on how far you bank the bike over Any form of lowering the footrests will have that effect.
