+1 on getting your seat cut down as a first step. Here's a pic of my CB750 seats - the one in front I pulled the cover and shaped the foam for my custom build. I brought the reshaped seat to a local auto upholstery shop. They covered it to my specs for ~$160. You can see the difference compared to stock - I took it down more than an inch.
Here's my 500 seat done by the same shop for the same price:
The trick is finding someone who knows how picky us bikers are about how our machines look!