Isn’t the RM43699 the 100-bay model?
Definately go for the 9300’s (or newer) as you want SAS3/12G
As others said the network size has been flat for months now: but it’s somewhat intentional. If your six IPs are all in different /24’s… you can probably still get 1-3TB/IP/year. Remember there are already almost 28000 other nodes on the network competing to use their space too.
For short-term: no - other than your system isn’t available to be sent more data, or paid to deliver it. If it drops below 60%-uptime (measured over 30 days) it will be suspended: and no further data will be sent for the node to store until uptime improves. If it’s offline too long it can be permanently disqualified.
Check out TheVan’s setup: he has links that describe his hardware. It looks like he has almost 650TB filled now.
It’s good that you have other reasons to keep all that space online: as Storj will not pay to run it alone. As I think you probably won’t even fill one HDD per year.
You should definately look at the Select/Commercial-Node program. If Storj needs capacity in your geography it could help you fill faster (if there’s paid customer uploads - since it avoids the /24 restrictions).