Well I am not sure if I really know what I am talking about, and this may be stupid, but:
1) you can't change the size? Just delete the numbers it gives you and enter '###MB' or whatever size you want to make the partition. 2) you generally want to have a smaller (50-100MB) root partition and a larger /usr partition as a bare minimum, and if you have the space to create individual partitions for /var and /home , you should do it. With 6.4 GB you have enough space. I am not sure about the intelligence of using a 1000MB root partition only. Just my 50 pesos, correct or not... --Anders