I would stick with the 50% water changes once per week. For me mineral levels tend to go up if I do less than that. I would also recommend you push your siphon hose into the substrate in places to reduce any organic buildup in the gravel. Organic buildup in the substrate can cause algae issues. If you do that in a random place every water change you will gradually reduce organic levels in the substrate. For the rest of the substrate just run the hose over the surface to remove surface buildup.
As to the rule of 1" of fish for every gallon, it is really a recommendation rather than a rule. I think it works best for fish that are 4" in size. For larger fish I think it over estimates how many fish you can have. for small fish it probably underestimates how many fish you can have. Most don't apply this rule to shrimp and snails because they have a "small effect on bioload" of the tank. In My opinion you could probably safely have 8 small (endlers / guppies) fish in there and a total of 3 amino shrimp and 3 Nerites. Unlike many tanks you have rapid plant growth which will help keep the nitrogen and organic levels safe, and therefore your water safe for the fish.
Since I haven't seen any new post in about a week I assume everything is going well.
As to the rule of 1" of fish for every gallon, it is really a recommendation rather than a rule. I think it works best for fish that are 4" in size. For larger fish I think it over estimates how many fish you can have. for small fish it probably underestimates how many fish you can have. Most don't apply this rule to shrimp and snails because they have a "small effect on bioload" of the tank. In My opinion you could probably safely have 8 small (endlers / guppies) fish in there and a total of 3 amino shrimp and 3 Nerites. Unlike many tanks you have rapid plant growth which will help keep the nitrogen and organic levels safe, and therefore your water safe for the fish.
Since I haven't seen any new post in about a week I assume everything is going well.