For a US startup I would divide annual revenue by aprox 200k for reasonable bootstrapped employee max size. So maybe 50 max? This is assuming standard software startup with most cost being employees.
It's not that much different in the EU. Through due to higher sales/revenue tax etc. a bit less employees. Also the additional cost above neto salary for epmploying someone is higher, but AFIK (especially as a startup) you can get away with a paying a bit less. Through in general it's less viable to scam your employees by doing stuff like goading them with non voting shares and then diluting them massively before selling. Like it's still possible but with much more limits. So this is comparison is limited to ethical company operation.
