I have usually done one pig of each batch I have taken in. I do really enjoy it and have learned a few things which may be of use...
You can get the pig back in halves or in primals (usually a half pig into three pieces) which are easier to handle - my abattoir/butcher doesn't mind which I ask for.
Knives - other posters are right - a bone saw, big steak knife and then a couple of boning knives. I really like Victorinox ones which are not terribly expensive and provided you have a sharpening steel they're great. Websites like knives.co.uk have good ranges.
Gloves are also a good plan to stop cutting but also allow you to grip as you cut.
Biggest challenge and most dull element of the whole thing I find is the packing and labelling. I bought a little vacuum packer from weschenfelder which helps but still takes longer than I ever convince myself is possible.
You need a big table / worktop to lay out half a pig and a lot of space to pile things up as you cut. I also have several clean washing up bowls into which I throw ribs, waste bits of skin/bone and then trim for sausages. I'm lucky and have access to an old unit with big butchery blocks. If you're doing it in a regular kitchen then it may be hard to handle / cut very large pieces of meat so would go for primals rather than half pigs. This still allows you to do joints or bacon etc.
Only other consideration which springs to mind is when you're doing it. If it's warm, then keeping the meat cool when you're cutting and processing a lot of meat is tricky.
Hope that helps
Martha