For the autobox gaskets and filter, try JPAT (£38 delivered). Dexron III from Halfords (£20 for 5l, need about 6 or 7l).
Yes, you'll have clearance on axle stands.
Although I bought 2 x 5 ltrs I only managed to get 5 litres in my car! :-?
If thats all it took, that's enough 
I reckon its normally just over 5l, and some lost depending on fill and check method...
..that's a good point - not sure how efficient that is going to be yet :-/
what's your method TB? my concern is that the hot exhaust is right next to the fill point..
I used to use a bit of hose, funnel one end, PCL air adapter other, PCL adqapter scrwed in fill hole.
However, I 'borrowed'

a garden sprayer from Ronnie McB which is how I fill now.
I use the DTM method - jack up passenger side, put in enough until it just starts to come out hole (with it jacked up), start engine, put more in until it has had 5l in total, then lower down. If any comes out, let it, then plug. If not, jack back up and put more in and repeat as necessary. Once the level is right, take it for 20min spin, then recheck level.