What arrows are you shootin now? Like Rich said, if the tail kickin high is all the problem you' re having just move your nock point down. If the spine was wrong they' d be kicking left or right. If a change is needed, I' d reckon trying something around 45-50# and 50-55# for wood arrows (I don' t know much about aluminum or carbon sizes). See which is closer to the mark and go from there. Othere variables depend on if you' re actually drawing 28" , how long your arrows are, and point weight. But if kickin tail high is the only problem I reckon you can work with your setup and fix the problem without change spine weight.

Brandan