Sounds like a good setup!
It's worth noting that the Hema app is simply a rebranded version of Memory Map. The main advantage of the Hema version is that they seem to be updating the Hema maps more frequently than occurs on Memory Map. The latest update apparently came with new GDT revisions. The ones via MM are still those which came with 2012 mapping and are "Copyright 2009".
The 1:25K topo maps will be the same as those that are sold via the Memory Map store. I personally find the 1:25K are pretty much useless for driving - especially on the iPhone. If you zoom in far enough to see the track, you end up not being able to see enough of the map to get context, but if you zoom out enough to see the context you can't see the track detail.
The Hema maps are about the right scale for use on the iPhone, and I was really happy using them when we did a trip up to the Flinders Ranges a couple of years back.
In Victoria the best Hema coverage is for the High Country. Elsewhere in the state the best you can hope for is highway touring coverage. Once you get into parks like Wyperfeld NP the information on the Hema's is woefully out of date. Many of the through tracks shown are MVO, and there is no indication of locked gates etc.
There is alternative coverage for this area from Meridian Maps and Westprint available via Avenza PDFMaps app but the app is pretty limited by it's lack of support of navigation based on tracks and routes*.
http://mapstore.avenza.com/public/62493/
http://mapstore.avenza.com/public/64037/
Until OziExplorer get around to building an app for iOS, PDFMaps embraces some navigation functionality, or Hema/Memory Map manage to get some of the other specialist vendors on board there is no single app with coverage that "does it all" for Victorian 4wd end users.
Thats my 5c anyway
cheers
Paul
* PDFMaps supports gps logging and user waypoints, but you can't load or navigate along tracks or routes. The app doesn't auto load maps when you move off the edge of the current map.

