so basically if your installing any version of win9x or winME
best common practice would be to install winME first on FAT32 on the first primary MBR partition and make it 8GB or under then you can install windows XP using the rest of the drive, and add secondary drives + partitions for more FAT32 space later on after the dual boot of ME/XP is complete. but the WinXP partition remains Hidden to win9x, because win9x cant have more than one visible primary partition, and the filesystem for XP is NTFS not fat32. the process of installing XP after installing winME does this all by itself and adds a dual boot menu at the start to pick between the two os everytime you boot. i had to resize my fat32 partition.
i used partition magic 8.0 to help with this
https://archive.org/details/norton-partitionmagic-8.05https://archive.org/details/powerquest-partitionmagic-8.0