The cage is ideally not subject to any loading unless you put them in the wrong way around. Given you have already partially disassembled things you may as well pack with loose. Ball Bearings are cheap.., You can grab a tub of 200 for about three times the price you would pay for just enough to do the job, 20?. Don't mix them. Use a complete set of new from the same batch.

More importantly whilst you have got things in bits check the bearing surface of the spindle for false brinneling, pits. If they are there then you will need a new spindle. Also consider buying a set of tools that are designed to work on the lock ring and cups. It may not be something you do often but they are nice to have. Either you eat crow or you spend money.

Don't forget that the fixed cup is likely to be reverse threaded. Prior to attacking it lay the frame on its side with the DS cup down and dribble some Dismantling Fluid, my side of the pond the brand name is PlusGas, in from the NDS. Leave it for a couple of hours or overnight and repeat. When you get around to removing the cup realise that you might have to be 'brutal'. Hold the tool in place with the flat of your palm and bang it with a hammer.