Shortly after posting this I started taking ModAlert 200 mg per day and completely stopped Vyvanse. Just bupropion 300 XL (brand name) and ModAlert 200 mg in the morning.
I did not feel any Vyvanse "withdrawal" symptoms at all, and in the past I have taken breaks from Vyvanse for around 2 weeks without issue.
For the first 10 nights I also had Hypnite 2 mg's (Lunesta) which helped bump my tracked sleep duration from max 6 hours to an average of 8 hours. But when I ran out I immediately regressed back to 6 hours.
Wakefulness
I can definitely feel the "clean energy" that modafinil brings. I can confirm it's not a stimulant at all, it doesn't "force" you to be awake, you just feel normal.
If you had bad sleep last night, modafinil can help you feel completely normal the next day. But if you sleep badly say 2+ nights in a row there's only so much it can do.
But unlike caffeine or Vyvanse, it doesn't "force" you awake and feel like your energy is being depleted and you're running on fumes. I never felt like modafinil caused/worsened insomnia.
ADHD
To be frank modafinil didn't do jack for ADHD.
Over the past month I felt more impulsive (confirmed by Amazon purchase history), time blind, low executive function, brought back bad behaviours like talking to myself out loud saying random offensive shit, having 50 Chrome tabs open to research 7 different things at once when trying to relax.
I basically regressed to my pre-Vyvanse self and this made me pretty unhappy. Work became harder, socializing became harder, relaxing became harder, I couldn't stay as focused while training, everything was just worse.
It reminds me of in the past when I have taken a short break from Vyvanse and then a week in I'm like "Damn, what the hell happened to me?" and then I remember how much better I am on Vyvanse and I happily resume taking it.
Effects over time
I know
@Ghoul has mentioned in this thread that modafinil's effects build up in your system over time. Maybe since it has only been like 30 days that wasn't enough time for me to notice anything.
But I felt the same on day 30 as I did on day 1, I didn't feel any "build up". My ADHD symptoms immediately became worse if I am being honest, but I didn't realize how bad they got until the past few days since the backlog of shit I have to do has piled up.
On the bright side I also felt the wakefulness was as good on day 30 as it was on day 1. So modafinil's wakefulness benefits are immediately apparent.
Current plan
Resume taking Vyvanse 50 mg and modafinil 200 mg in the morning along with bupropion 300 XL.
Re-introduce Hypnite at 3 mg before bed to increase sleep duration.
Advice
Modafinil is perfectly fine, I don't really see a reason to take armodafinil. I never really felt like there was a time when modafinil "peaked" in my system since it's so clean.
200 mg was a perfectly fine starting dose and I am glad I didn't waste time splitting pills and titrating up.
If you take Adderall/Vyvanse continue taking it while you take modafinil and let it do its thing rather than treating it as a replacement.