Higher Impedance MC Carts on Transimpedance Stages?

Similarly, the gain you will need from transimpedance stage (assuming it's like an SUT into MM phono) is given by:

G = 5R / V;

where R is cartridge resistance (plus tonearm wire) and V is cartridge output in mV. For example, an 0.3mV cartridge with 8 ohms gives G = 133 ohms.

Yes, gain for a transimpedance stage is given in ohms... 

I worked this out. Bandwidth is where current is half of maximum. This occurs when impedance from cart inductance equals cart resistance. If the bandwidth is acceptable, cart will run fine.  Bandwidth is given as:

f = R/(6.3*L);

Or you can use the handy calculator I placed on this web page:

https://www.hagtech.com/loading.html

There is no real contribution from phonostage, since it appears as a dead short, we are talking transimpedance, right?

Nevertheless, first order bandwidth rolloff is from L/R ratio of cart (and tonearm wire). Think current, not voltage.

I know it may feel counter-intuitive, but what is happening here is a sacrifice between output amplitude (maximum current) and bandwidth. 

Input impedance of my transimpedance stage is a function of opamp gain. Let's say we have a 100 ohm feedback resistor and an output voltage of 1V. That means input current is 10mA. Forward open loop-gain of opamp in question happens to be 85dB at 1kHz (IIRC), or roughly 18,000. Hence, voltage across input terminals is 1 divided by 18,000. This defines an input 'resistance' of 1 divided by 10mA and 18,000, or about 6 milliohm. In reality, this worsens with trace width, solder joints, connectors, etc. 

As for the gain equation, it was a simplification. The '5' represents 5mV, as a target output for an SUT-like stage. So units are R*V/V = R.

For bandwidth, the criteria I set was for 1/2 signal (-6dB voltage). Sorry if I had typed -3dB earlier. It's just a simple empirical rule-of-thumb I created to determine the likelihood of an LOMC operating into a transimpedance stage (or equal resistance loading). Half output current occurs when impedance from inductor equals winding resistance. Impedance of inductance is X = 2*pi*f*L. Set X = R and solve.