Hi,
From my ( veeeeery limited ) understanding that would depend on what you feel the possible morph might be.
If you think it is possibly an example of an existing morph with an identifiable homozygous form then you would probably breed it to another definate example of that morph - or the homozygous form if it as available.
If there was no definitive homozygous form then you might go for an easily identifiable combination.
If the possible morph might be something new then you would possibly want to keep things simple to help you work out the genetics and so breed it to a normal.
Or you might just breed it to anything you can get to see what happens.
dr del