Well, it's messier when it's in the car but still quite doable.
The rear two sump bolts have a screw slot in them - if they're as original that is.
I used a 1/4" socket on a longish extension to get to the ones near the bulkhead. If your car has the bracing plates across the corners where there side rails meet the bulkhead you could drill a couple of holes big enough to get a small socket in - a previous owner had done that to mine which made the job easier though the hole was only big enough for the extension bar.
With the engine out you normally put gasket sealer on the block and stick the gasket to that, then drop the sump onto it.
With the engine in the car I put sealer on the block but put the side gaskets on the sump using a couple of bolts in place as guides. A bit of tape over the heads holds the bolts in. The gaskets over the main bearings are a bit tricky. Fit one end, hold it in place with the sump at an angle and then put the other end in.
I use the jack to hold one end up as an extra pair of hands. It's definitely a job where you feel like you want three or four hands, especially trying to line up the bolts.