I would drop to 1600 speed on the ram. 2133 can be problematic, and it is also unnecessary. The default speed on Intel boards is 1333 so you will have plenty of cushion with 1600.
I would also opt for 128gb on the SSD. The 60-64gb sizes are proving to be problematic from a disk management perspective. Even if you install a program to the hard drive, it will still dump stuff in the Windows directory. Just the way Windows works. Once you get Windows fully up and running on the SSD, then plug in the hard drive and set up using this procedure. http://www.pcworld.com/article/237496/the_best_of_both_...
Not really sure of the effect of SLi on drafting apps, so you may want to research the Nvidia site on that.
Would there or is there a significant difference in the 2133 vs. the 1600 or 1333 as far as RAM goes? Also, the 64GB or 128GB SSD has been a bit of a debate for me for a while now for the reason you have stated. I have friends who have used the 64 and been very well off and ones who stand by using the 128. Not sure what I am going to do yet.
With the exception of using 1866 speed ram for AMD APUs, which has shown to improve performance, there is no advantage I am aware of in going beyond 1600. For stock speed Intel systems, 1333 is optimal. I have 1600 speed as I got a great deal a while back on a 16gb kit which I split between my two rigs.
1600 speed is also desired in case you have to make "adjustments" for overclocking. Although, with the k series Intel processors, you generally do not play with the system bus. You typically just adjust the multiplier, so realistically, you could still overclock with 1333 speed ram.
I do know with CAD, it is more about the amount of ram than the speed, so 16gb will help there. For gaming, you will be hard pressed to even use 8gb for a while yet.
Tom's did an article on the ram speed thing a while back proving the insignificance of speed and other parameters. You can search Tom's or Google if you want to know more.