Why not swap cams? I know it's a little more work, but why mess with a lot of little things when you could just change one item and be right where you want to be.
I do like the idea of putting weight where you need it, in order to improve cross weight, but I am sure that you running a tight suspension. I would think that it would take more than 20 pounds to make any real difference in the cross. How much weight would you need to add? Also, do you have your own scales to measure that down after you get HP dynos? Also, if you are going that far with weight, wouldn't you want to change it, since each track has a different setup? Seems like a lot of changes, but that's OK too.
However, a nice custom ground cam to deliver peak HP and torque in the RPM range you would want. Any ways, just a thought.