Hi I will invest to any idea about earn bitcoin. I would start from 0.1 BTC. If everything will be ok I pay more more money 
I wait for PW
why you will start with 0.1 btc .i will suggest you if you want invest btc at any site then invest not more than 0.001btc . because in the presence time no one site is honest . every site ran away within month . I wait for PW lots of sites have higher minimum investment than 0.001btc. so it is not possible to invest 0.001btc anywhere. but I understood what you exactly want to say.. and I agree with you..
Yes. start investment from as less amount as you can. because if the site ran away with your money your loosing amount will be lower.. you can increase investment after confirming and proving everything.