It's always best to have a bit more freezer space rather than less, as it can be tricky to fit everything back in together when the freezer is packed full. I have 200 litres (7 cubic feet?) and that is
enough for 1/4 of a large beef, plus a few other bits and pieces. This size freezer could fit half a large beef, but it would be a struggle to pack everything back in after rearranging.
A trick I have for better freezing quality is to alternate layers of already frozen stuff with layers of raw stuff that I want to freeze - e.g. if i have some frozen pork roasts in there and am freezing beef, I'll put a layer of beef, then a layer of pork, another layer of beef, and this helps to avoid freezing a massive slab of meat in one piece.
Beef mince/ground beef and sausages seem to be the slowest to freeze, so putting these in a few different places helps them to freeze faster than if they'd been all in one piece.