Straits Settlements, East India Company

You can avoid almost all counterfeit coins by purchasing NGC or PCGS certified. It rarely costs more and by buying them already TPG'ed you avoid the other hazard, which is cleaned coins.

The less able you are at grading the more sense TPG make.

You're usually spot on Mox but I must disagree strongly with that notion. Slabbed coins usually carry a substantial premium (for many obvious reasons) than unslabbed ones.

Straits Settlements Victorian silver in higher grades can be quite pricey. I understand your need to identify high quality fakes.

When it comes to authentication and grading, stick with the CCF.
You will definitely increase your grading skills, if you contribute to the grading threads.
Best to say WHY you think a particular coin should be graded the way you think it should be. Others may disagree; that is how you learn. That has been my experience, anyway.

A bonus:
When looking closely at a coin picture, you also learn to find indications that a coin may be a fake, or a different variety or an error. Also works with ancient, hammered and milled coins.