Which kws should I target first? I am stumped

In a new niche I am getting ready to go at full bore, for adsense optimizing

I have created two domains they are up with wordpress on them and a sticky article on the main page, and both are aged one month since indexing

I have about 20 kws I want to target all in this niche
I have some that have about 5000 exact searches per month that have , the first few sites showing actually ZERO backlinks

Then I have a few kws that are 15000 searches which of course is better

One I found has 10,000 searches per month and the backlinks to the page
shows for the 1,2,3 positions on google ..........as 0,0,6 respectively

this would I guess be the best one to target first since it is the highest traffic lowest backlink combination...............

How did I find these kws? pure luck. I HOPE that soon other people dont start targeting them and then if I do get number 1 rankings soon will have to bust my butt to maintain them, but I guess thats a possibility.

These kws were extremely hard to find and I know I know its almost impossible to find kws with that high search traffic and low backlinks

btw the CPC on these is $3.50 on average, which I hope means they are good

There are a few kws that have 15,000 or 18000 searches per month EXACT local, and I wish these had such low backlinks but
well for example there is one with 15k monthly searches but
the backlinks showing on the first 2 sites is
11,and 96 backlinks respectively

Would you
if you were me , target about 10 of these kws simultaneously? and just spread the backlinks between them since the 15k/month search kws would probably hit number 1 (hopefully cross fingers) within 1-2 months, since even though their backlinks are considerably higher, they are still very low in comparison to most sites out there

or
would you target the ones with 0,0, on the top two listings showing for backlinks, and say well those should be WAY easier to get number one on............get those number 1 listings then after that go on to the harder more competitively backlinked kws (those are mostly ones with 5000 local monthly searches.

I am thinking if I do target those 0,0 ones, wouldnt it be smart to also be throwing up 40 to 50 backlinks a week on the more competive terms as well? so that those backlinks can start aging?