Speeding up the creation of Instance from a several megabyte string

[jplauri]

I'm creating a somewhat large model and creating a Model via the add_string method. Then, quite a bit of time is spent on creating an instance of Instance. My Minizinc instance when written on the disk takes about 8-9 megabytes.

The docs don't seem to touch upon the issue, but are there some general guidelines or best practices to apply when handling instances of this size (or larger)?