I have had some success doing that. Didn't have the problem you have but felt my tail bone was carring too much of my weight. Took my seat to a nearby auto/boat upholsterer and explained what I thought I needed. I asked for more padding on the outer portions (sides) of the seat to get more support under the outside of my butt to carry more weight there. He was able to do that with the existing cover without any additional cover material. That was last fall and I haven't had a chance to really test it with a long ride yet but from what I have ridden, I think it's going to help a lot. Cost was about $100 - $120.