I've read that the general thoughts in Belgium when brewing with spices is that if you can taste the specific spices, you've used too much.
For a five gallon batch of my Inner Sanctum Triple, I use 9g total of spices (no orange). For a five gallon batch of my White Tornado Wit, I use 14g spices + 7g chamomile + 1 orange peel (of course this has a lot thicker mouthfeel, so the viscosity plays on this). This is about the top range of what I would recommend (for my palate, anyway).
My best advice is to try a batch, see it through to completion, take careful notes, and adjust accordingly next time around.
"Sometimes when I reflect back on all the beer I drink I feel ashamed. Then I look into the glass and think about the workers in the brewery and all of their hopes and dreams. If I didn't drink this beer, they might be out of work and their dreams would be shattered. Then I say to myself, It is better that I drink this beer and let their dreams come true than be selfish and worry about my liver."