I now have five 51E reels (2 curados/ 3 chronachs) Planning on using these for everything, from the east coast of Canada so all I fish is smallmouth. Just looking to get steered into the right direction on how to find/obtain replacement gears to change the ratio in some of these reels (if it's at all possible). I'd like to slow one down, and speed 2 of them up.

Im not sure theres a "slow down" gear change available. The core 51mg7 gear set will get you to 7:1.

The slow-down option is the 5.8:1 gears from a JDM Aldebaran MG.  It only gets you a reduction of about 2 IPT so you have to decide if the cost and effort to source the parts from Japan is worth it.

 

It's middle geared so all you really need is to speed up or slow down a little. I use them for all my techniques and haven't found a reason to spend anything to upgrade the ratios for such a small margin of retrieval