Turntable/arm/cartridge VALUE combination for 600

If you are not opposed to used, your money will go a lot further. Used VPI, Rega, and others can be had for what you are willing to spend. There are a few in the adds right now.
Sturgus

...which model depends on your budget, but I would go with the most recent upgrade possible, so 7.1 (I would save a few bucks and go with the 5.1 and use saved money for some new vinyl.).

which music hall models should I target? The MMf7 or 7.1?

The Music Hall tables are good values and when upgrading you'll get most if not all of your money back.

IMO

I ended up going with a VPI HW-19Jr when looking in that price range. Lots of flexibility to upgrade platters, motor, arms, etc when money permits. A number of folks had recommended this on other forums. (Full disclosure: I am selling this table on AudioCircle, but you can also see the posts there that led me to my purchase. I have now moved waaay up to a Well Tempered Amadeus).

A used AR ES-1 or EB-101 are very good turntable/arm combo and sell for about 400 dollars or less used. Mine came with a shure M97xe cartridge which is pretty good for the price and I agree with the NAD mm/mc phono preamp it is very good and I have 2 of them. The model is PP-2 or PP-2i for the updated version. Happy Listening. For best results use with a tube amplifier like my stock Dynaco ST-70 which is still a killer amp after 50 years!

Forget it. Save up for something better.

Rega TT are well known for a high price/performance ratio. Look at th the P2 and used P3. Go with a NAD phono, you can find them used b/t $75 - 100.