On a side note, I've never messed around with the cart. loading in my preamps. Would this change the character of the highs at all?
Yes - it absolutely would change to an extent.
Think of loading of a fancy tone control (not to slight anyone that employs it, but that's what it is in effect). So, it won't change the character of your cartridge, but might change your perception of it as you dial it in to your taste, system, etc.
While it's not the most important thing to get right with vinyl...it's an added twinkle that can often help. For lower output cartridges such as you have - it's sometimes essential to diddle around with it. For instance if your MC input is the std 100 ohm loading point...it's probably much too low for your medium output Benz.
The result would be (a generality here as it's system and person specific) overdamped. Lows would sound too tight and highs would be generally characterized as too loose or diffuse. Moving up the loading to, say, 800 ohm (I'm just picking a number, mind you), you would loosen the iron grip on the bass and put a little more structure to the treble. Mids might snap into focus a bit better.
You'll still recognize your Benz under all that - but it might take a sonic character more to your liking.
Ciao, John