How high do you need to get the car to do this ?? Got all the bits now, and I have 4 standard axle stands and a trolley jack ! So can I get it high enough to crawl under and drop both sumps ?? Not looking forward to this one .... sounds VERY messy 
I'm not too comfortable about using axle stands at all four corners, especially as I never manage to position them well at the back anyway.
When I did mine I drove the back of the car up on to a couple of scaffold planks to give a few more inches clearance and the front on axle stands - obviously its just when refilling that it needs to be level, so you can hoist it up higher for the sump removal/refit.
The messiest job I found was scraping off all the old gasket from the transmission mating surface.
Refilling I did with a funnel and length of hose. SWMBO poured in the fluid and I held the hose in situ and clear of the exhaust. I'm sure there are better ways though.
It took quite a lot more after starting the engine - at least a couple of litres I think. I used 6-7L in total.
HTH
Ian