CJ,
Yes, it would effect the tone, no doubt. You need to balance the aesthetics vs. tone for your particular tastes. Clearly aesthetics are an issue, otherwise we wouldn't care about having custom colors in the first place. Making the poles come closer to the strings will increase the output seen at the preamp or head's input. As long as you are fairly accurate in adjusting all of the poles equally, the overall tone curve shouldn't really change... but the output WILL increase. Whether this is a good thing or bad thing is highly subjective and will vary on a per pickup basis. I just wanted to make sure that people thinking about the Bobbin Toppers knew that there was a concern as far as the thickness of the "sticker".
Regs,
Jeff