Reading this and having everyone come up with fuzzy math and future projections really makes me think you haven't been in this business long. Will envoy have a flow? Yes. It's part of the business model and keeping pilot cost in line. Will it be fluid and dynamic? Yes. Will in change in your 6 to 12 years to flow. Yes. Please don't be fooled and think someone can project another company's future needs.
That being said. Pick envoy because it's where you want to be. Unfortunately envoy is not a stable regional. Crew bases open and close at a snap of the fingers. They transfer company aircraft to other regionals just as quickly. Reserve love is horrible, and will last for years. Your pay is often wrong so keep an eye on it. They also violate the contact regularly so file grievances. I have won thousands of dollars back but was it worth the hell and stress?
Hopefully envoy can fix the bugs that have pledged this company for the last 3 years and infected the employees you would be working with. This is just my advice. But you have options so interview ask questions, do your homework, and pick a regional corporation you are ok working for 10 years.
Don't plan on staying for 10 years, but pick a place you would be ok at for that time.
Happy hunting