As for why I want it up front, it's because it's a helluva lot easier to get it sorted now than it will be in two years when my skills are dated and I'm competing with every other schlub for dwindling jobs.
That said, I am actively looking for part-time and contract work in my field that would set the ol life:work ratio right. Gliding into RE as it were. If that doesnt work out and megacorp does, I'll megacorps for 8 months. If neither work out I'll RE very soon and figure it out as I go.
I can relate to this. I thought about FIRing early (
thread), but I'm glad I stuck it out a little longer. Ultimately, the optimal FIRE date is hard to set precisely within ± 6 months, so you make your best guess given all information at your disposal.
If you're 35, that's a long time not to be earning another penny... My guess is that in 2-3 years, you'll have enough of your side-projects and you'll find something else to do that will pay money. Not sure if you're in IT, where it's easy to snatch a contract here or there. The pay is lower than at mega-corp, but if your FIRE date is at least roughly in the right ballpark, it won't matter too much.
Also I'm surprised you get picky about not wanting to reduce your expenses too much in the event of a downturn. Is it because of hard constraints or just because you feel like giving yourself maximum luxury? You could do your costly "project" for 2-3 years then work a little to pad up your stash.
But again, I agree with your general approach. Patience is key.