Welcome Bacer.

It is indeed a great question.

I really do believe that hosting videos on your own servers will look much better and more legit for your surfers, your videos may rank better too but you will have to upload all content yourself, so it surely will take a lot of time.

You also have to be prepared for a big hosting bill. Streaming adult videos cost a lot. Especially when you are marketing to a lot of freeloaders.

If you are just starting out, I do not think you want to jump into the tube site market. The bandwidth costs of said sites is horrendous and conversion rates generally suck pretty good. It takes a lot more clicks to make a sale.

I do have adult sites that embed videos and they do quite well too.

May I suggest starting out with the tube theme from XWPThemes, they recently reduced their prices on all their scripts so it is totally cheap at just $40 or less, and these themes work fine with the most popular tube sites. So set up the script, import the massive amounts of hosted videos that are available, then give your hand at promoting it and getting traffic.

That will give you a good taste for a tube site without costing you an arm and a leg in bandwidth, and also saving you the hassle of checking user uploaded clips for legality.

There is no minimum number of posts you should add. I would say, the smaller your niche is, the less you should post.