I don't like filtered clunks in tanks, since I don't like pulling the tank out every few months to clean the filter however filtered clunks in jugs are a good idea. I do like in-line filters - they don't hurt any and might help. It doesn't matter which side of the firewall it is, what's more important is that it's easy to get to, so you're not discouraged from pulling it apart periodically to clean it, and that you're not filling the tank through the filter - hard to remove filtered gunk if you keep blowing it back into the tank.

I use (fairly unpopular) "quick fill" devices from dubro, and install the filter between the quick fill & the carb. If you don't use the quick fill you either need to remove the fuel line from the tank side of the filter to fill the tank, or install a 3rd unfiltered line with a fuel dot.