VAXStation 4000/90 Hard drive options

Hi all, A quick question for the VAXen experts out there. Help would very much be appreciated. I'd like to know what the maximum drive size is that I can attach to my VAX. I've never been given a definitive answer, but many people appear to have had success with drives larger than those 'officially' declared supported. I will be running OpenVMS. In particular, I'm wondering whether a Seagate ST39173N which is a 9.1GB 50 pin device will work. There are also several 4.3/4.5GB 50 pin models available, as well as a huge number of 68 and 80 pin devices that could be connected via adapters. I bought a Fujitsu 9.1GB 80 pin SCA drive and attempted to connect this to the VAX via an 80 - 50 pin converted but the drive was not recognised properly by either the boot rom or OpenVMS. Thanks for the help, Mark.