You can use a MAC address generator for services like IKS66. A MAC address with the prefix of 00:1A:79 will work with your STB.

If you're looking for a hassle free alternative, I would suggest using IPTVsubs or SportsAccess.

since you asked about IPGuys, I have them, and when you order it, they provide you with the MAC. and it's not just the last 6 digits, I think that is for the NFPS/IKS Stalker PVR client specifically

I use IPGuys on Kodi 16.1 with the built in Stalker PVR without issues.