I searched Vinyl Asylum and found some generally good comments about the Alpha 9's phono stage, so I'm leaning toward other upgrades. In no particular order...
The Zero's will stay until I get a proper sub, hopefully an NHT that will blend well with my setup. If I can't find a NHT sub, perhaps I'll look at a Hsu.
I have not experimented at all with cart loading, and I probably won't until the new sub is in place.
I will revisit the turntable setup. The current alignment took me the better part of one evening, but since it was my first time it would not hurt to recheck everything.
As far as speaker placement goes, I have some latitude with the sub but virtually none with the Zeros, which I have placed at about ear level (when seated), about 10 feet in front of me and about 6 feet apart.
Thanks for all the suggestions and insights. That's why I posted here.