Brandon, interestingly I use the Fred Eichler split finger tab. There is just enough space between my fixed crawl nocking point and the arrow nock for the index finger and index finger portion of my tab to fit nicely. My middle and ring finger are below the fixed crawl nock.
Some guys will use serving material in place of the fixed crawl brass nock to help lessen the effects of "shooting over" the fixed crawl.
It can be done and I've done it. No major noticeable downfalls. If you are shooting a 3 under tab, then there might be some awkward feeling bump under the tab.
I typically set up my fixed crawl close to hunting season. During hunting I don't shoot at deer over 30 yards. For all off-season shooting I dedicated string walk all my bows without the fixed crawl nock on the strings.
Hope that helps,
Matt