@adversam Yep, still vinyl only. It wasn't so much a problem to solve, rather than a specification that I learned to pay attention to. I'll provide my (fairly limited) understanding on the issue, but I'm sure others can add to it. The quality of the external phono stage is irrelevant for this discussion - a high quality stage and a cheap stage with the same gain and the same cartridge will put out the same voltage.
To keep the math simple, the standard 40db/60db gain for MM/MC corresponds to 100x/1000x amplification. So, if you have a 4mV MM cartridge, your MM phono stage will put out 400mv (100x4mV). Similarly, a .4mV cartridge into an MC stage put out the same 400mv (1000x.4mV). Of course, the phono stage will output more voltage on musical peaks.
I'll now use the example of two different integrated amps that I have demoed at home. The first had a very low input sensitivity of 1.2v (note: higher numbers = lower input sensitivity). So, my 40db phono stage wasn't even putting out half the voltage needed to drive the integrated to full power. This amp sounded terribly dull with no dynamic punch. The second integrated had a high input sensitivity of 125mV, so my phono stage was putting out more than three times the needed voltage to drive it to full power. On this particular amp, I couldn't use much of volume control range - it got very loud very quickly.
I've found the most success in choosing integrated amps that have an input sensitivity a little lower than the output of the phono stage, but not significantly lower. So, with a 400mV output from the phono stage, integrated amps with input sensitivity in the 200-350mV range have worked the best in terms of having good range on the volume control, no overloading, and still maintaining a full, dynamic sound.
I'm just sharing my personal experience and my admittedly limited knowledge on input sensitivity. Others may correct some errors above, but I'm pretty damn certain about my experience :).
Cheers,Scott