Storing block blueprints in memory

So I was wondering, what's the best way to store a set of small (5x5x5 or less, mostly consisting of air) blueprints of blocks in memory for comparison or construction?

My initial thought was to use an object list that looks like:

Code:

int xOffset;//-x or 0 or +x from starting position
int yOffset;
int zOffset; 
// block data

Then write custom get/comparators/etc. This way a blueprint that only has for example 8 blocks but takes up say a 3x5x3 cube would be relatively smaller than a matrixed array including nulls/air.

Does this seem sound?

 

Yes, that would work. I actually created a utility plugin for myself that used this same idea, but rather than storing the blocks to variables, it would write a method to file which would replicate them given an origin.