Best thing to do would be to contact the
support ninjas - off the top of my head, this sounds like a document and/or stencils imported from the Mac version are chewing up a bunch of resources. iPads are amazing pieces of hardware, but they do have much slower CPUs and much less RAM than most desktop machines.
Stuff can usually be adapted to work just fine on the iPad - here's an
example - but a bit of tweaking is sometimes required. We're happy to help.