Midsurfacing complex geometry

I am currently working with fairly large models that consist of a number of parts that are castings.

In order to keep the element numbers down in the model a number of the castings are being simplified using midsurfaces.

The castings that are getting midsurfaced have a large amount of uniform thickness material  whcih is fairly easy to midsurface but they feature a number of more complex areas featuring bosses and varying thickness material that makes midsurfacing very difficult and time consuming.

As the auto-midsurface can not handle this geometry a large amount of manual midsurfacing work is required and this has is very time consuming and frustrating, partly due to Hypermesh not being the most stable platform for creating midsurfaces manually. I have had a large number of problems when equivalencing sides and replacing points where Hyperworks seems to carry out additional, unwanted, actions (eg. toggling 2 edges and it will effect points or edges that I do not want to move).

Has anyone had any experience doing this that can offer me advice or tips? Or is it just a case of being persistent with it?

Will