I'm not a crazy whipper by any means, but sometimes it's absolutely critical to whip. I do so mostly in the early game when settling my first 5-8 cities, and at any time when I need a fast military buildup. In the latter case in particular I will sometimes whip very ruthlessly indeed because a critical war is usually the decisive point of any game and what use is having a couple more population points and a few less angry faces if you lose the war?
Apart from that it's occasional, the main instances being:
- if I have very production-weak cities they obviously need to be whipped or they will never have any infrastructure;
- I often whip a university or two to speed up Oxford;
- caravels - if I want to get out there fast and meet AIs I'll often whip one or two as soon as Optics comes in;
- coastal cities in general get whipped when they run out of useful tiles and start working coastal ones. The same applies to any excess population or citizens that work unimproved tiles.
To answer your specific questions (and again, I probably whip less than I should so take my answers with a pinch of salt):
[*]Do you whip for Workers and Settlers? If yes, do you ever do 1-pop whips or always 2-pop whips for such units?
Absolutely, settlers in particular. I usually revolt to Slavery as soon as possible and start whipping settlers because getting the best city locations is vital. 2-pop whips are obviously preferable but I will 1-pop whip too if I feel a settling location I want is threatened.
[*]Do you whip 2pop when the city is not unhappy (but at happy limit) and for which units/buildings would you do that?
I 2-pop, 3-pop and sometimes 6-pop if the situation calls for it.
It all depends, if it's a city that doesn't work superb tiles and I really want to build something important there, then the unit or building in question is much more importnat than the population points.
[*]Whipping vs chopping -> After I tech/trade for Mathematics, I find myself chopping like mad and forget to whip. That suggests I'm losing production by not whipping - what's the best way to combine whipping and chopping? Do you pick it by city type/need or do you grow to max, whip, then while the city grows back you chop (which is what I try to do myself but always forget/can't time it correctly).
It's often hard to combine both without running into hammer overflow loss, whicn rather defeats the purpose and wastes trees and people (unless you're playing that mod that converts excess overflow hammers into gold).
The only things you might build that generally cost enough hammers to absorb chops and whips together are wonders which come with a penalty for whips. I still whip them, though, if I'm serious about building them and not just going for failure cash.
As for how I might space my whipping and chopping around the empire...well it depends on where your workers are available. It also depends on whether you want to save trees for a wonder and all the other things I mentioend before about how usefully the poulation points are being employed. Population grows back a lot faster than trees.
[*]Considering the city growth bar, do you whip when it's at the beginning or when the city is 1 turn or 2 from growing?
Assuming you have a granary, which you should, the growth bar will only be between the halfway point and full, never lower. If you don't have a granary your population is probably so low that it doesn't matter, since the food requirements are very small (say you are whipping a monument as your first build, for example). So I generally don't worry about that so much.
[*]For buildings do you whip as soon as possible to finish it? Or do you time it so that there is some kind of overflow?
It's hard to generalise here as it depends on how important the building is, how many expendable tiles you have that you don't mind not being worked for a couple of turns, how many hammers you can put into it without the whip, how strong your food for growing back those population is, and probably other variables too.
[*]Do you use the Avoid Growth button? I mean not like activating the governor to it - just so that you can work food tiles but the city doesn't grow.
Sometimes. The problem is that I forget to turn it off again, so I try to avoid using it.
when you can instead of using "avoid growth".
