For passive play (golden switch on): Radiant Appetite and Breath of Milk
Spirits are: Cow > Asceticism > Jeremy
For active play: Radiant Appetite and Dragonflight
Spirits are: Godzamok > Cow > Jeremy

For godzamok how do you use it effectively, do you like sell all you farms in a dragon flight or something?

Godzamok increases the power of clicking by an amount proportional to the number of buildings sold in the last 10 seconds. So the thing to do is use it when you get something that already boosts clicking power, such as a Click Frenzy or a Cursed Finger, then sell stuff and start madly clicking for 10 seconds. I sell everything from cursors down to banks. (I haven't tried selling temples as I don't know what would happen - whether that would cancel the effect of the spirit - and have not dared try.)
I already have the building buying option set to Sell All, ready for any Click Frenzy that happens. (Or a Dragonflight - but be aware that a Dragonflight effect only lasts for 11 seconds, so don't spend all your time selling buildings leaving no time for clicking.)

Buying back your buildings, or nearly all of them, after the frenzy, won't cost much by comparison with the cookies you generate during the frenzy. Selling and rebuying would cost less if you have the Earth Shatterer aura active, but if it's not already active it's probably not worth taking the time to install it when a frenzy happens - time that should instead be spent selling buildings and then clicking.

Some time ago I proved that in the long run, after playing for a time t, cookie production is proportional to the square root of t and total cookies is proportional to t^(3/2). This results from the fact that CpS is proportional to prestige, which itself increases as the cube root of the total number of cookies.

I did this before the introduction of the Birthday Cookie. BC adds an additional 1% to the CpS for every year elapsed. This means that in the VERY long term (we are talking about decades and centuries here), production eventually becomes proportional to t^2, and total cookies becomes proportional to t^3.

All this of course assumes that people will still be playing Cookie Clicker in 100 years' time. If they are, then I imagine Orteil's grandchildren will have implemented many fixes and improvements, one of which will probably be to limit the maximum benefit from Birthday Cookie. Or maybe they won't. When your number of cookies is in the quinquidecillions, a factor of 10 here or there may not be considered worth bothering about.

You can see the effect of Birthday Cookie in this graph. Both axes are on a logarithmic scale. In the early years, the slope is close to 1/2, reflecting the fact that production varies as the square root of time. At about 30 years the effect of BC becomes noticeable, and after several hundred years the slope approaches 2, indicating that CpS is proprtional to t^2.

I think most forum members play this forum in "idling" mode.

I haven't been using it, but according to the Wikia, the cycle runs according to Universal Time, with one of the negative to positive crossover points always occurring at 0000 UTC.

You couldn't use litres though, the Americans wouldn't understand it

They would soon learn! In fact the game might be a good educational tool.

Or if Orteil really wanted to go over the top he could have a setting on the Options screen to choose whether to display milk in litres or express it in furlongs or cubits or whatever arcane units they use over there.