hey all just a suggestion, you can use a step drill bit for fitting modules and making holes on plastic and metal very clean ones too. I use them i would suggest the brand unibit though as they are the best but expensive around 20$ or you can buy a 3 pack chinese ones for about 13$ on ebay!
like these http://cgi.ebay.com/28-size-3-pc-HS...ryZ50383QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
like these http://cgi.ebay.com/28-size-3-pc-HS...ryZ50383QQssPageNameZWDVWQQrdZ1QQcmdZViewItem