On a pro plan. Use opus 4.5 with thinking enabled. I find that two sessions eats through my entire five-hour "session limit", so no need for parallelization because I've consumed my tokens before I can even blink.
I see the power and am considering Max but 5x cost is difficult to swallow. Just doing this for a lark, not professionally.
I have 2 max accounts and still hitting the limits almost daily. Vibing 3 projects simultaneously.
I like using Zed with Anthropic API Key. Burned through a few hundred dollars in a weekend but got the Rails app to work about 10x faster than trying to hire someone.