Hello everybody, this is my first indoor grow, cur...

I always seem to get variation between seeds even of the same strain , the only way to stop this is growing clones , but you can't clone autos 👍

Your plants look great relax smoke a bowl and enjoy

You’re growing 2 differents strains, it’s normal, it’s all about genetics. Some plants grow fast and big , others grow slowly and stays small. For example a Girls Scout Cookies will grow slowly and won’t get too tall compared to some XL strains who can reach 180cm in the same amount of time. Heat can be an issue you must make sure to water more often and try to keep RH high enough.

Agree, nothing wrong with the different growth from different strains, it's normal. As for the temperature - you need to get fresh air into the growbox, so that tiny PC vent isn't going to do it, a few of them might, but if you can get a proper vent in there, air movement as well as air exchange is very important to healthy plants and healthy environment

Nothing wrong with one been taller than the other, even if they were the same strain, it's nothing strange that ones develops faster, but since they are different strains, it's even less strange. High temperatures do make the plants grow slower, if you could keep your temperatures below 29°C that would help a lot. Try some LST and topping, in order to keep the height of the taller plant in check, while the other plant catch up