This does not really sound interesting and the best you can get are spammers to boost your forum posts since users needs to make 200 posts or start 100 threads in order to earn $10 quality shall be compromised.
Any suggestions what I should do? Would be glad to hear?
Everything depends on your budget which I will not like to overstretch.
The lowest paid to post forums normally pay $0.02 per post and $0.03 per thread.
My suggestion is that, you can increase the payout since you are paying with your token which might not be listed yet.
High pay rates will attracts users and might stabilize your forum even when you stop paying people.