You can...
1) Go to a store and sit in them before buying
2) Go to an office, see which chair you find comfortable, and consider getting serious about your purchase by buying something that may be more expensive than what you initially had in mind
or
3) Continue wasting a bunch of time...
If you're on a tiny island in the Pacific, why are you concerned with what car you drive? Sounds like you need to get a bicycle if the place is so small.
I know you're probably in love with it, but did you ever consider just upgrading to a larger case that fits your needs?
There are many RAID cages that you can buy to convert your 2 optical bays to support 3 3.5" drives, but that adds an additional cost of at least $50 and still leaves you a...