Alright, it has actually never been shown that the first tomoe could see chakra, but that's something different from the Naruto base Role play verse since in the Role play it is possible to see chakra with the first tomoe. However, the user is able to track speed with the first tomoe but isn't able to see everything in slow motion like the third second and third can, however it can perceive the motions as you can see in the Sasuke and Haku fight. but for now you can still believe that 1 tomoe gives you access to perceiving irregular chakra flow.
Alright, something about viewing chakra, the Sharingan doesn't allow you to enhase your field vision like the byakugan increasing range of sight however it is able to see the difference between which element your opponent throws towards you, you can clearly see the difference between when someone uses Fire, wind, lightning, earth or water against you. Wind due to the vibrations of lightning chakra, the density of earth chakra, the flow of water chakra, and the thin blade characteristics of wind, and the fire is hot.
Another thing for you to know, you can only break trough visual genjutsu's with the sharingan. Visual means that genjutsu that affects your sight making you see illusions and what not, however it's not the only genjutsu, there are genjutsus which makes you hear illusions..
Understood?