Answer from cs61c-cb (Minh Uyen Nguyen 16765774) for Question 2
Virtual memory allow a single user program to exceed the size of primary memory.  It automatically manages the two levels of the memory hierarchy represented by main memory and secondary storage.
The benefits of having the VM system allocate pages in fixed-size chunks are: it eliminates the need to find a contiguous block of memory to allocate to a program.  VM also provides the  tools for relocation problems.
Having  a larger number of virtual pages than physical pages is the basis for the illusion of an essentially unbounded amount of virtual memory.
Bigger chunks mean bigger pages, a page should be large enough to amortize the high access time.

I cannot really get any info about what's good about smaller chunks.