Solid Hardwood, Engineered and Laminate Flooring - last 4 rows and mixing putty to match the color

I am installing 3/4 solid Brazilian Cherry (extremely hard-wood). I have come to the end wall and I can no longer nail down the tongue part (I did the prior row manually). I would like to know if it is acceptable to put basically 2 face nails (at each end of board)on boards under 2 feet long and 3 nails into boards over 2 feet. I am finding it difficult to match the stain with putty to fill in the holes. Also, can you tell me how to fit the last couple of rows flush to the adjacent row. I know to use a crow bar but can someone explain the technique.

To snug the last few rows up, you can use one of three things:

(1) a "last board puller" which has a lip at one end to fit over the hardwood board and a flange near the other end which you can pull or pound on.

(2) a screwdriver or crowbar pounded into the subfloor next to the board and then used to lever the hardwood. I've had limited success with this approach.

(3) a "power jack" which you can ratchet against the far wall (with a 2x4 to prevent damage to the wall). This by far is the most sure method. It will exert all the force you want and more.