vSphere dedicated server specs

I'm a freelance software dev and security researcher and I'm comparing two servers for use as a dedicated vSphere server which I intend to use to host machines for a small software development and security testing platform. I'll also host outward facing FTP and VPN services, perhaps a mail server for one of my domains (only a handful of users for all services). In total I suspect there may be 10-15 machines.

I'm not hugely experienced with vSphere, doing most of my work on my machine at home using Workstation, but I spend a lot of time on the road so the ability to centralize a testing and development platform should make a huge difference.

The two hosted servers I'm looking at are detailed below; the trade-off is CPU vs memory. I'd rather make a good decision early than try to port things over when I realize I've made an error so any input would be appreciated.

Option 1:

CPU: Intel Xeon D D-1520 2,2 / 2,6 GHz RAM: 64 GB of RAM DDR4 ECC 2133 MHz

Option 2:

CPU: Intel Xeon E3 E3-1231v3 3,4 / 3,8 GHz RAM: 32 GB of RAM DDR3 ECC 1600 MHz

All other specs remain the same.