To be honest bro you're not going to learn much spending only $6/day. There is just not enough data.
Before you dive deep into your optimizations and analysis, switch to another geo or even placement that you can at least spend $50/day.
You need to get those clicks and conversions going before you can do any optimizations etc.
Edit: Sorry forgot your questions lol. My answers are as follows:
1. I think this is a matter of preference? How I analyze is really dependent on what I'm testing (ie offers, landers etc)
2. I never use the pass through on TJ, I just ballpark estimate what my CPC will be and enter it into
3. In my opinion there is no "best network", every network has it's ups and downs. I disagree though that TJ is a good network for newbs. All the newb guides you see say TJ is a good place to start. This may have been cool 5 years ago, but now I think it's a super affiliate battleground lol. I think for newbs TrafficStars, Traffic Factory, and even Exoclick are better choices. I still buy a lot of traffic from TJ (low-mid 5 figures monthly), but if I had to do it all over again I don't think I would've started on TJ. I lost a lot of money there when I first started out lol.
Nowadays I REALLY doubt a newb can go there and profit easy. Traffic is just too expensive, you need a good funnel and a good payout to make it there, and usually only advanced affiliates have this lol.
As far as your question about Pornhub, yes it varies by geo in my experience. This is the same for all the sites (ie Redtube, Youporn etc) meaning depending on the Geo the spot could be gold or complete trash. Also obviously how well you do will be dependent on how good the offer is in that geo as well. So there are a lot of variables to consider.
4. Ripping is a good place to start, I think trying to reinvent the wheel in adult is dumb. You are going to have to start testing variations though of what you got (ie new angles, new images etc). Just ripping and running isn't enough to be profitable.
5. Again I think you need to switch to a spot that has more volume so you can get more data. Good luck.
Thanks @jabong82, I appreciate it man! I'm going to take your advice and take this to another spot/geo. Thanks again!
Jabong pretty much answered all the questions and I have to say I agree with most of what he posted, if not all 
So just a few thoughts for you:
- running the "deep" analysis with such low amount of data is really pointless, there is a lot of "coincidence" affecting the numbers. All it takes is one or two random leads and you could be doing the wrong decision. Some ads can perform well with certain traffic that you were lucky to get, but as soon as you expose them to more eyes, they will lose steam. The only way of getting significant data is... well, to buy more data 
- traffic costs will never be accurate, it's technically not possible with CPM bidding. Every banner has a different CTR which messes up the stats a lot. The only way to reach high accuracy is to analyze the banner one by one on each spot, which can be time consuming. What I'm doing is similar to what jabong mentioned, I just try to get as accurate estimate of the CPC and use that in the tracker. Then, when I see some spots are close to being negative or around the breakeven point, I check them separately to make sure the numbers are in my favor.
- TJ is really not that newbie friendly as it used to be. Just a year or so ago, I could get to breakeven easily with pretty much anything, but it's not the case anymore. Not sure if it's just the block selling or they lost some good SE traffic, but yes, there are more newbie friendly sources now... TJ still works though, but it takes more effort than before. BTW: I think the second largest site after pornhub on TJ is youporn, you can try there too, sometimes it works better than PH.
- ripping works great for the start, it's really pointless to try and figure it out all on your own, ripped creatives can work great as benchmarks. But, you really need to start modifying stuff soon, small changes can make all the difference and if you're not doing them, you're leaving money on the table.
Cheers,
Matej.