I certainly see why you wanted to include those filters. Large scale projects with multi banded images are very interesting and add flavour to any image. With any luck the finder will offset the weight, but I think you might have to put something on the front in the opposite position. Often getting balance can be difficult and the one thing that the SB mounts require is very good balance. You should not have the counter weights on the RA offset at all. Perfect balance is the goal. I don't think it will be a problem, just something to bear in mind if you cannot get DEC tio balance out perfectly.
Yes it does look pretty good just sitting there.