How many BPT do you usually have before before you start wanting to build building?

I like to get up to 50 bpt pretty quickly

Whats a good average limit for the whole set?

I use 50 to 60. That doesn't mean im right. its 4 turns for one BPT for most governments so choose how you spend your turns wisely.

how hungry are you for acres ? :)

anyway.. based on start ups.

if you target to have abt 10k acres.. u would need about 60bpt. (50 bpt off the bat to start off if you do a 180 cs start up)
15k acres about 75bpt.

there is a formula somewhere.. just search the forum.

sqrt(land goal/4*1.4).. i think..

You can start by repeating the cycle of building a full BPT and then 4 construction sites (5 turns total), and keep doing that until you reach at least 60 BPT. That's the way we used to do it back in the good ole Earth 2025 days. It still works pretty good now.