From off line discussion:
It seems worth to add some more VM properties to the project configuration page in more explicit way. In particular max heap size. One possibility will be to have Visual C like UI where you can tick some checkboxes but you also see full options string and can edit it.
*** Bug 173800 has been marked as a duplicate of this bug. ***
I take care of this.
Done, the feature is provided by changeset #deaf66f1703e