The MAX space that u can allocate for a DS depends on the storage medium and the space available on that volume.
In DASD 3390 model, you have 1,2,3,27. If your shop is using 3390-3, then you will have 3330 cylinder's of space available for that empty volume.
Space allocation happens in extents, to allocate the maximum primary space for a DS in a DASD volume, check the largest free # of cylinders available and use that number to create the DS with a large primary qty. The secondary space is not contiguous(there are parameters in SPACE that can be used to ask for contiguous space) and hence, the maximum, qty only depends on the storgae size of your shop.