Welcome to the SeeMeCNC Community

Original Rostock Max V2 hotend (.5mm orifice) vs e3d hotend (.4mm orifice).

Recalibrated everything using the same methods from when I was using old hotend, changed the EEPROM using mattercontrol (extruder nozzle set to .4mm). How do I get better XY adhesion (spread?) at the base of my model? Kindof regretting "upgrading" at this point...

Printing in ABS at 228* for old hotend, now using 233* for new hotend (was getting poor adhesion at 228* with v6).

Maybe my Z height is too high?

What you are observing is most likely (the photo is actually very clear) due to not changing the layer height in the slicer. What layer height did you slice these parts? Remember, when you decrease the diameter of the orifice, you should think about the affect on layer height. Take this example:

You printed .25mm or maybe .3mm layers with the .5mm stock hotend and then switch to a .4 mm hotend and kept .25mm or worse, .3mm layers. Now you have much less of the bead hitting the build plate and you see the "roundness" of the bead like in your first photo. This can of course happen with a Z height too high too but it is much more common in cases like yours that you did not adjust your layer height. I typically print at .2mm layer height with my .4mm E3D hotends.

If you regret buying the V6, PM me with how much you want for it and I'll take it off your hands, I need a couple more.