Gumps is just a way to memorize a flow. Nothing more.
And respectfully, I disagree. A checklist must be in written form, paper or electronic…. But not memory.
lol…. Gumps, and variations of it, are more of a flow. Use whatever flow you want… Then back it up with the WRITTEN checklist.
Some DPE’s may be forgiving on that, but that is the correct way to do it.
There is no reason you cannot get the clearance on the ground, depart VFR, and get your release airborne.
That said, I would depart with a 1200 code, not the discreet code. That may give them a coronary.
I don’t know….
I could not begin to recite what all the requirements are for a specific certificate, but I certainly know there *are* requirements and they can’t be skipped.