Large DVD burner machine - multiple sata controller advice required


I’m building a system using 16 Optiarc 7200 Sata drives. This is not for DVD duplication but for burning individual isos (I already have a custom script to handle this.)

Have a gigabyte GA-8I945P-G-RH motherboard, the 4 onboard sata ports will be used by internal sata II hard drives.

The motherboard has 3 PCI, two PCI-E x2 and one PCI-E x16 slots.

Basically I need advices in choosing suitable sata controllers to enable me to connect the 16 sata dvd drives.

Does anyone have any experience in conecting sil4726 port multipliers to sil3132 PCI-E 1x cards?

Or should I be looking to use 4 port controllers, one on each PCI-E 1x interface, one on the PCI-E 16x interface and one on a PCI interface?

Thanks in advance