The fat pads biggest influence on clamping is that you might not be able to get the clamp as far down at the base as possible.
Actually to hold the clamp as low as possible I always use a second clamp which greatly helps in that endeveaour.
I clamp with one clamp as tightly as I want and then I apply the second clamp while holding the first towards the pubic bone.
This creates a tight fit of the clamps towards the pubic bone without much hassleduring the set in regards to maintaining that.
I most the times clamp with the first clamp in a way that it enables me to still kegel some blood in.
The second clamp I then use also as a sort of valve to control blood in and out flow.
Done in the right way the second clamp doesnt create much more tension then one but gives the above added benefits.