whats the best way to use mass video blaster

hello guys ive just got myself mass video blaster and i have 1000 accounts to use but im not sure whats the best way to go about uploading and how many video per account and should i stay on one niche im currently doing a test at the minute to send them to a landing page were they fill in there details to win a iphone 4s its not cpa its my own site were i get there email details. but will do cpa at a later date and do you keep the same watermark on all videos you upload id be grateful for anyone who can help