rickyricardo;2252861; said:
			
		
	
	
		
		
			Can you explain how you make those cuts in the 4x4's.
		
		
	 
This question makes me really wish I took a lot more pictures.
I actually cut all 4 pieces at once.  This was a time saver. 
My first step was to to make all 4 pieces one with some large clamps.
I then laid them down on my workbench and fastened them with more clamps to make sure they wouldn't move.
I picked up a 2x4 and used it to make the approximate measurement. While the 2x4 was handy I used it to set the depth on my skill saw.
Now that I have a line and the correct depth I moved my 2x4 to become my straight edge to guide the saw.  For my saw it's 3/4's extra distance from where you want to cut.
I use clamps to lock the 2x4 in place and double check all my measurements.
I then cut the 4x4's all the way across.
That's one cut.
Now I unclamp everything.  I make sure to turn all the 4x4's 90 degrees in the same direction.
 
I use the same set up for the first cut that I do for this.  I make the second cut.  I now have two sides cut.  I need to cut the top now.
Leaving the 4x4's clamped together I pick them up and stand them up next to my work bench.  They are way to short, so I had to put a box under them to raise the tops of the boards above the workbench standing straight up.
I clamp the 4x4's to the work bench side.  I draw my line.  I set the skill saw depth to it's maximum.  (Which isn't enough.) And free hand this cut across all of the 4x4's.  
I unclamp everything, rotate 90 degrees, and reclamp. I draw my line and make the second cut across the top (4 cuts total).
I now essentially have all my cuts required. However the vertical cuts are not deep enough. So I unclamp all the 4x4's and work them on an individually.   I use a hand saw and a chisel to finish the cut.  I could have used a reciprocating saw, however I wanted a clean straight cut.  If you have a decent hand saw these cuts will not take much extra time.
Sorry I don't have pictures. They would help tremendously in this discussion.
If you have a table saw these become even easier. I don't have a table saw that fits in my garage. YET.  I have a very nice table saw that takes up to much room to put in my garage. It's currently stored in a barn at my aunts property. (2 hours away.) 
Hope this helps, it's really hard to describe how I did it without pictures for your reference.