It's usually best to make the /boot partition primary if you have a seperate /boot partition. Else make root (/) on a "real" partition.
The only reason it matters is because the limitations of the x86 bios to access the partition to load the kernel into memory to continue the boot-up proccess. And I don't even know if it's nessicary for things like Grub, since grub relies very little on the hardware...
Otherwise it doesn't matter.
Anyways having lots of little partitions makes things complicated. On machines that are linux only I only have /boot, root, swap, and /home seperate. On systems with other OSes present I just keep it to root, /home, and swap. For simplicity sake.
Also if you want to keep it easy on yourself, install Windows on a primary partition, and then leave the rest of the system unpartitioned and unformated. Then just let the linux installer figure out the rest for you.
(keeping in mind the limitations. 4 primary partitions limit. If yoiu want more you can make one of the primary partitions (number 4) into a extended partition and divide that up between numerious logical partitions)
