I just had this issue at work. Not impressed with all metal hot ends, not a big fan of exotics either. We have a 3mm e3d at work and PLA didn't work with a .4mm nozzle, switched to a .6 and PLA is fine now. I think extrusion was so slow heat was creeping up the filament itself and hardening/friction in the cold section. Unless you already have ABS I would use PET it is way easier than ABS.
30x30 comes out to about 25x25. My machine is asymmetric, no big deal at all. Hard to explain but bed size means nothing, you just need to pay attention to part size. Not using end stops makes it much easier my slicer thinks my bed is 2Mx2M it doesn't matter. doesn't matter what axis is shorter at all.
Support tubes for rigidity, no problem I plan on whipping some up in the next week or 2, I need them for something...
When you get to that point I can make a 25mm holder if there isn't already one out there. An outrunner spindle is cool, That was the original plan, but store but trim routers are cheaper and less work.