Domination HUD entity set-up

So I was planning on designing a map that has the same qualities as dom_canalzone, i.e. 8 points, domination style.

My question is: how would I set up the entities for the domination gamemode? I can figure out how to set up the 8 points neutral, but how do I link them to the HUD in order to make the domination percentage appear and rise in accordance to the number of points owned (like dom_canalzone)?

I could not find any of this anywhere, as no pages exist detailing setup for domination maps and I cannot figure out how to put changing text on the HUD that rises proportionately to the number of caps owned like canalzone does.

Thanks in advance.

(I hope my question does not confuse you: I am asking how to set up a percentage based HUD element that will rise proportionately to the number of caps owned (and how to make the team that reaches 100% first win), NOT how to put capture points on the HUD nor how to set neutral 8 point CP up because I know how to do that)

So I decided to decompile it like yyler said and there was a lot of math_counters. I'll be looking into the map and figuring out how to make such a game mode.

Ravidge, how close does that prefab come to an 8CP dom setup? I'll have to look through it again but the main reason I didn't want to use that is it utilized a jail and I wanted it to be more player-friendly like canalzone (that's an oxymoron but oh well)