So he wants to mine stealthily without being discovered by others or university network admin.
I am also curious about it.
Would be better to explain it in general (not related to op's case). Since you have those kinds of service, right? As far as I know, using VPN will increase latency, means more steal shares, right? May you can explain more, besides what I told.
The VPN will indeed increase the latency affecting the time to get job, time to deliver share and also time to restore connection if your ISP network quality is bad. So more stale share probability I confirm.
Assuming the university has probably a good connection to internet and considering the will of OP to keep its mining rig secret, I could only encourage him to use a VPN despite the counterpart of latency (because of a longer network route and the VPN transport layer added over TCP/IP), risk of more stale shares, ....
Rigproxy.com is not a VPN solution but a proxy. When you go through a VPN (online pro service, or at home with RPI/linux) or any other tunneling solution, the admin can only see your VPN target IP.
If you connect directly to Rigproxy, the network admin may know that you are mining so using rigproxy won't help for privacy and was never made for this purpose.