Alex Tumay, Young Thug's trusted right-hand engineer received all the stencils for On The Rvn days before he was arrested on drug charges, except for the Elton John sampler which he started on a few weeks prior. When you account for London on da Track's post-production work on each song, followed the surprise announcement Thugger made days before getting arrested, Tumay and his staff really only had like a day and a half to whip the final edits into something "consumable."

The astute professional he is, Tumay finished his mix and master session with the allotted timeframe, the pushback came from Young Thug's legal situation and series of sample clearance issues, which required time to work themselves out bureaucratically. Tumay says that beyond the factors outside his control, and a few minor details on "Climax" with 6LACK, everything came together quite organically. 

The origin for the "Rocket Man" sample on "High" was one of the major plot points Tumay outlined in his interview with Noisey. Apparently, the song started as a pipe dream two years ago, dating back to an encounter where Young Thug summoned the courage to ask Elton John's permission to sample his famous song. The two men shook hands, expressed mutual admiration, and that was that: the wishful path for "High" and the rest of On The Rvn was born.

Alex Tumay then swore to keep the Elton John's permittance a secret, until the song was Godforsakenly leaked earlier this year, through no fault of his own. Check out the rest of the Noisey interview detailing the 36 hour process that was: finalizing On The Rvn - "on the gun."