For a lower poster that only writes 2 post per day, your offer is good, about 0.001 per post of a member.
However, some members post 40 and 50 constructive posts PER day and with this kind of posting rate 0.0006 per post (or even 0.0005) is much better.
Anyway, good luck.
Yes, and here the rate is same for member and full member. Active Full Members are making 0.0008 per post @ UpDown.bt. So it is too low for active members. Now for low activity members, I have 2 suggestions...
1. Give 0.001 BTC per post as U r giving along with the max cap of 50 posts. But dont have a lower minimum. If someone does not post, he wont be paid. But dont force a non-active member to post. That would I guess attract a lot of people, but wont cost u more a dime.
2. Continue the weekly payment.