Leave it in the corporation, or pay it out and invest personally?

What this simplifies, on purpose: corporate investment income is modeled at a flat ~50% combined tax rate on growth each year, without simulating the Refundable Dividend Tax on Hand (RDTOH) refund's exact timing and amount — a real mechanic that would improve the corporate path's result somewhat, not modeled precisely here (see the RRSP-vs-corporate comparison for more on why RDTOH matters and how much it can move the answer). The corporate path assumes the accumulated balance is eventually paid out as a non-eligible dividend, taxed personally at your stated withdrawal-year rate. The personal path assumes annually-taxed capital gains at the 50% inclusion rate — a diversified equity portfolio realizing gains every year, not interest income or deferred gains, both of which would change the personal side's result too.