Fair enough. Though, I'm not forking it for others, it's for my own server until the event gets PR'd (server side only mod), which I'm sure eventually will just not in its current state.
Edit: Finally got a day off work, and I figured it out. Posting solution here for search engines.
To make a long story short, I copied the cached gradle directory of the forge version I forked (2489) and named it as build 0. I then cleared the mcp mapping directory in the snapshots directory. I then placed my userdev jar in the cleared directory. In my mod I set my forge to build 0 and ran setupDecompWorkspace and ForgeGradle built all the other jars and md5 files needed.
I've attached a screenshot of the directory I cleared, with my userdev jar highlighted. All the other files there ForgeGradle built for me. I hope this helps the next person that finds this thread from searching.