TigerVNC + XRDP on RHEL 7 (this shouldn't be so hard!)

A couple years back I set up an XRDP server on one of our RHEL 6 timeshare hosts for general desktop use by a few Windows users who wanted a RHEL GUI desktop on rare occasions. This was before systemD and I remember it being mildly annoying to set up but once it was put into place we achieved something resembling feature parity with Microsoft Windows wrt RDP capability.

Now that we are chucking our RHEL 6 timeshares I've started looking into the state of XRDP and TigerVNC on RHEL 7 and I am sad. XRDP is luckily heading to EPEL 7 proper (from testing) within a few days it looks like (https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2015-8153), but when I install that and tigervnc-server on my EL7 timeshare nothing but sadness and woe ensues.

The underlying problem is that I can't seem to get tigervnc-server to "just work", so xrdp-sesman can't connect the login session to a tigervnc session.

I've checked the latest guidance in the system administrators guide for TigerVNC and it's all oriented toward the most user-unfriendly implementation only* - having individual systemD unit files for each named user etc etc.

I tried creating a service account 'tigervnc' for the systemD unit file and that didn't get me where I was hoping - here's my unit file for reference:

$cat /etc/systemd/system/vncserver@.service
[Unit]
Description=Remote desktop service (VNC)
After=syslog.target network.target

[Service]
Type=forking
# Clean any existing files in /tmp/.X11-unix environment
ExecStartPre=/bin/sh -c '/usr/bin/vncserver -kill %i > /dev/null 2>&1 || :'
ExecStart=/sbin/runuser -l tigervnc -c "/usr/bin/vncserver %i"
PIDFile=/home/tigervnc/.vnc/%H%i.pid
ExecStop=/bin/sh -c '/usr/bin/vncserver -kill %i > /dev/null 2>&1 || :'

[Install]
WantedBy=multi-user.target

Which isn't even recognized by systemD as valid

 $systemctl start vncserver@.service
Failed to issue method call: Unit name vncserver@.service is not valid.

...despite guidance that the :# portion of the unit file isn't needed**

Is there any chance that someone less dim than I could please get TigerVNC and XRDP playing nicely on RHEL 7 and doc it so that I can regain feature parity with Windows?

Thanks!

*https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/System_Administrators_Guide/ch-TigerVNC.html
**https://access.redhat.com/discussions/1149233#comment-883903