Gabriel Aul, from Microsoft has posted about how all the build's release decisions are made in Microsoft (check the picture to understand it clearly). However the main point of posting this is Microsoft is also planning to do add a new option called "Ludicrous speed ring" other than the already available "Insiders Fast" and "Insiders slow".
With the help of "Ludicrous speed ring" you will be able to get the preview builds even before "Insiders Fast" but this also means it will have lots of bugs and issues with the builds because they won't be passing through all the levels of testing.
However if you think you're brave enough and ready to take the risk and not scared of those tiny bugs then vote up for this "Ludicrous speed ring" idea here at Windows Uservoice
SOURCE : Windows Blog