It is such a good gesture on your part to organise $200 freeroll which will be exclusive to BTT community. If I may ask how do you ensure barrier to entry? Don't just post password (if password protected) publicly here as it will be exploited by many cheaters. Instead adopt a PM based approach to who ever is interested, of course you have to ask for interest first. I know you are looking for numbers but quality wins very quantity in long term. We have already seen sone case with basepoker where few cheaters registered almost 100 accounts  to just exploit $100 freeroll. Negative marketing is worst.
Also I will suggest you to take a look a the timings of existing poker contests so that there will be no clash and players don't have to compromise     
This will give you an over look: https://bitcointalk.org/index.php?topic=5551413