Weather influence on restumping?

My house will need to be relevelled at some point in time, and some stumps need to be replaced I think. One is leaning over a bit (not just sunk), so I think that will certainly have to be replaced.

Anyway, does the weather have any influence on when to restump? My house is in Ipswich, so I suppose there's a fair bit of black soil and clay. The house does seem to move around a little bit when there is lots of rain (as we do now) and when it is very dry (as we did 6 months ago). Would it be best to wait for the weather to settle down to a more "average weather" before getting it done? Or should it not matter at all?

Also thinking of removing 2 stumps to make the garage more accessible (and replace the two individual garage doors with a single), one of those stumps is not holding any weight at the moment anyway. Reading around these forums (and thinking about it) I'm a little concerned that this will put more weight on the surrounding stumps - is this generally a problem? I'm probably going to get two of them replaced anyway, maybe I can get bigger beefier stumps to support the extra weight?

Also, does anyone have any recommendations for restumping companies? Sort of looking into Heritage City Restumping at the moment, but would be open to any other suggestions.

Thanks :)

These are like the ones I made up at Work.
Like the TYPE M30, Double Nutted.

http://www.scottmetals.com.au/column.html

Easy if you have the facilities of Cutting implements and Welders.

I put down a Footing of Concrete, about 400mm Wide and 400 to 450 Deep to sit mine on.
They were only about 500mm long.

You can set then their own Concrete footing;
just make sure you have enough adjustment with the threaded Rod
for later adjustment.