new fsx PC

Hi there! I just finished building a new PC last night, and I have one question regarding it.  First I'll list the exact components:

Case: Rosewill Thor V2

MB: Asus Sabertooth Z97 Mark I LGA 1150

CPU: Intel i7-4790k Haswell 4.0Ghz

RAM: G. Skill Ripjaw X Series 16GB (2 x 8GB) DDR3 1866mhz

PSU: EVGA SuperNOVA 850 G2 850W

Video: EVGA Geforce 980GTX

CPU Cooler: Corsair Hydro Series H105 liquid

Storage: (1) Samsung 850 Pro 256GB

               (1) Samsung 850 Pro 512GB

               (1) Samsung 840 Pro 512GB

System has been assembled, Windows installed...so far everything works great, but I haven't had time to do anything else (install drivers, overclock, etc.).  My question is this: The OS (win7x64) is installed to the 256GB SSD (obviously).  I'm planning on putting FSX on the 850 pro 512gb.  Will that be big enough for FSX plus all my addons? Stupidly, I forgot to check how large my current FSX install + addons was on my old machine before taking it offline.  I run quite a few scenery addons, the largest pack being FTX Global + Vector + FS Global, plus all of the FTX NA regions as well as Australia/NZ.  I also use quite a bit of plane addons, including all the PMDG planes + liveries, several of the Carenado's, Masjestic Dash8, Wilco CRJ, Embraer Regional Jets, all the RealAir planes, Airbus X Extended, and several other payware planes.  I also use REX4 + ASN, and some other bells/whistles such as Ground Services X, FS2Crew, FSPassengers, and some others.  Will all this fit on one of the 512 drives, or should I buy a much larger mechanical HDD to dedicate to addons? I'd rather not do this if I can help it, since I bought the absolute fastest SSD's currently available and would like to make use of them, plus the fact that I've never split up FSX and it's addons between drives before.  Just fyi, the 840 pro ssd I was planning on using for all my other games that I'll eventually install, so for the purpose of this post it'll be off limits for anything FSX related.  Thanks!