Tube Preamp Paired with Tube Phono Stage?

My experience is as per Lewm's and Syntax. I run MC's into 47k tube preamp, Marantz 7 modded, which although it is only 60db TOTAL gain, can easily handle MC's 0.3mv up with no noise. I also had a Klyne 7 which seems to emulate tube pre's in that it is designed to run mostly 47k and use very high frequency contour filters to handle the resonances. I found 47k plus filters at around 50k plus were the go.
The Klyne has been despatched as it was easily outperformed by both the Marantz and my tweaked Theta tube preamp from the 80's.
I have generally found that the MC's with very low internal impedance such as Koetsu's ( 3 ohm ) etc run fine into 47k but have occasionally had issues with MC's with higher internal impedances such as Denon 103D ( 40ohms ) and Benz ( 40 ohms ).
I have a gut feel that the lower impedance MC's in general will do better into 47k.

Actusreus,
As far as I know the input impedance of an amplifier will have ramifications in the first gain stage with regard to bandwidth, gain etc. Therefore the chosen input impedances provided by any particular phono stage may have as much to do with the design of the succeeding gain stage as it does as with the designers choice of cartridge. No doubt many designers are trying to second guess what customers are going to buy and their preferences for loading.
It can be a chicken and egg - which comes first, cartridge or phono.
Mostly what we are buying in an analogue front end, including the phono stage, are a cocktail of complementary colorations.