1) I setup my repeater behind a firewall, but there are cases where both the SC server and the Viewer might be external. I opened both ports 5500 and 5900 to allow for sc and the viewer to link to the repeater from external connections. (this allows my bosses to take a copy of SC home so I don't have to make house calls anymore) In the following helpdesk.txt script examples, I've used your.website.com in place of the external IP address of the firewall. If you are using SC on an internal network, you'll use the internal IP address instead.
3) The order of syntax in line 2 of the [HOST] section must be in the right order.
I originally incorrectly entered:
-connect your.website.com:5500 -id 1234 -noregistry
THIS DOESN'T WORK
and I still don't see why it didn't work but -id must come before -connect:
THIS IS THE RIGHT WAY
-id 1234 -connect your.website.com:5500 -noregistry
and for encrypted connection it should be:
-proxy -id 1234 -connect your.website.com:5500 -noregistry
3) For some reason the MSRC4Plugin.dsm I originally downloaded didn't work and caused the SC to close in error. First off, be sure to place both this file and the rc4.key file into your custom folder (the instructions I followed originally didn't say to copy the MSRC4Plugin.dsm file, just the rc4.key one).
once I had done that, the MSRC still gave errors . I fought it for the longest time, then I found this thread: [topic=3278][/topic]
If your encryption doesn't work, start from scratch and follow this guys instructions (thank you REDGE!

4) For some reason my firewall wouldn't allow port forwarding of 5500. I don't know why (probably because it's old), but I got around it by just using 5501 (I did the same thing with 5901 instead of 5900). I forwarded these two ports to the repeater server, then went into the settings of the repeater program and changed the ports to match. Be sure to change "restrict all ports" to 0 so that it allows both server and viewer connections in ModeII.
5) It took a LOT of tries to get everything in the helpdesk.txt file correct. Instead of having to make a new .exe file every time, use WinRAR to open a previous .exe file and copy the winvnc.exe file into your custom folder (the one with the helpdesk.txt file). You can run this file prior to zipping up the folder... it works just like the .exe file without having to build the .exe file every time.
6) The repeater log is your friend. You can watch the log and see when/if the SC and viewer programs have made connections. you can also see error messages if you did something wrong. This was helpful when I couldn't get port 5500 to forward to the repeater. I changed to 5501 and could see immediately that this new port worked as expected.
7) When connecting to a repeater, you use IDs to link the SC (or UVNC server) and the viewer together. In the Viewer, the Server name is listed as ID:1234 and the repeater is the repeater IP followed by the port number (5901 in my case). For the ID you can use any numbers you want, but it must have the ID: in front of it. I attempted several connections with just the numbers before I realized that ID: was required.
Conversely, when editing the [HOST] section of the helpdesk.txt file, I tried using -id ID:1234 like the guide tells you to. This didn't work for me. Once I removed the ID: everything worked properly. My script looks like this:
-id 1234 -connect my.website.com:5501 -noregistry
(my.website.com resolves to the external IP of my firewall)
I'm sure I'll think of more, but hopefully this will aid those who follow in my footsteps.