In answer to your question above - the 0.6SI and the 0.4SI...

In answer to your question above - the 0.6SI and the 0.4SI Magnetic shells are those purple and pink shapes in the map view, I am not a geophysicists but those Mag shells are basically generated by Geophysicists using the Mag data to construct a theoretical shell or lump of magnetite bearing rocks that best match/explain what the observed magnetic fields are at the surface (and also from any down-hole readings or magnetic data from previous drill holes). I like to think of them as a geophysicist's "best guess" or suggestion as to what is a likely body of magnetic rocks and is useful for planning drill hole locations and directions, remembering that sometimes the best copper or gold zones may not necessarily be in the highly magnetic core or zone but may be adjacent or zoned around the peak magnetite body. Thats why in early IOCG exploration you often see multiple drill holes to drill perpendicular to the magnetic pipe or tabular zone to test for these situations. All the geophysical models end up being superseded by the reality of the actual drilling if a discovery is made, and the geophysical models end up being simplified versions of what is the reality from the drilling and then mining. But the models are useful for finding, ranking and planning drill holes, especially with concealed or blind deposits.

Early explorers often banged vertical holes into the centre of a magnetic feature which may itself have been subvertical. Then they walked away when the drill hole came up with high magnetite but no copper or gold. Increasingly with better geological knowledge and better more detailed geophysics the resolution of the mag data allows more interpretation and a better plan of attack with drilling to learn as much as possible, with the least amount of drilling (which can be deep and expensive).

The screenshots you have included give a very good explanation of the different targeting methods and different types of IOCG deposits and how they may look at the surface by magnetic and gravity geophysical methods.