i found the link for the effect of different locations of patches - this is the writers summary of the paper she has read - she does include a link to the paper but there is a sign-up required. Hurdity is quite right, its a US site, hence the focus on compounding etc. But given the reports people have given about patches, weight loss, location questions etc I thought it was quite useful link. See
http://surmeno.blogspot.co.uk/search/label/patch. The quick summary is "As a rule, though, best results are obtained in the outer half of each body half, but not so far "around the edge" that there's a lot of curve to the location and not directly over an area where there is little padding over the bone or over large muscles.
The other location factor is that studies by manufacturers have shown that patch delivery (same patch, same dose, same degree of adhesion, different location) varies by 17-25% depending on whether it's on the front of your body or back. That is, locations on your butt deliver more to your system, from the same patch, than if it were placed on the front of your body."