If you can't find a sensible tilt that keeps all the soft bits happy, then I'd try something else ASAP. If the sit bones are sore when you've been off the bike for more than an hour or two, then I'd try something else ASAP. If it's just the sit bones that are hurting and they're not sore when you're not on the bike, then perhaps give it a little more time for yer bum to toughen up.