Following thread also covers info regarding "using larger disk" such as 4GB/9GB (max 9GB). It's an older thread, but it should apply. I have simulator 9.10.1 and it allowed me to add additional two shelfs (2 comes pre-configured by default). I don't if there has been any changes in 9.12.1.
vsim_makedisks -h (In the disk-type list, numbered 31(4gb)&36(9gb) can give you additional larger space.
Give it a try: I am guessing if you add remaining two simulated shelfs (14 disks each) of disk type 36 , you will get to substantial aggr data size (Not sure if you get 200GB but something close to) . But, make sure you have the space to add such large disks.