If you plan on bringing the buffbot with you to PvE, then def. go with the 40 enhance spec, or something close to 40, I don't know exactly what it is for a Cleric.
On my Druid I used... well I don't even remember anymore, 37 or 38 enhance? I used the typical RvR spec for my Druid who was also a buffbot. The only drawback is that I lost about 4 points of strength and con when buffing, but who cares. I would bring the Druid to buff and heal in PvE, use the same spec for RvR, and the same spec for being a buffbot at the border keep.
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