Wow, it's difficult to give an answer to that question. Instead, what level of player is the course planned for? A beginner's Par 2 ability is much less than a 1000+ player's Par 2 ability. Are you planning for the course to be a mid-range/putter course? Or a 'every disc available' course. A 250 ft hole is Par 2-able for quite a lot of players. Heck, I can throw that distance with a 5 speed and I'm rated in the mid-600s. But a beginner might not be able to make it in 2. A 1000 player? They are probably using a putter and going for an ace.
Start with what level of player you expect to be playing it most frequently and plan for that. Multiple tees, same thing....what level of player do you envision playing from each tee pad (realizing of course that most players will play from the longs even if they shouldn't be)? Figure out how far that level of player throws and adjust accordingly.
With multiple tees, you could even include ratings on each sign Red < 700, White 700 to 900, Blue >900.