Watering through would be good for solo cups at this point, but not the 2 gallon pots. It would take too long for the the 2 gals to dry, preventing the roots from getting oxygen, the soil also wouldn't be getting air & would sour. You can water through once you see roots coming out the bottom. Just seeing some roots coming out does not mean root bound. Root bound is when there's more roots than soil. At two wks old, they're not big enough to be root bound even in solo cups. If you want to check roots, pick up cup/container, tilt to the side, tap the bottom, turn a little more & gently slid out. Plants (any kind) grow better when the roots barely hold the soil ball together. That doesn't mean its time to transplant. You'll get used to this & know when its time for that. But when you transplant, go up ONE pot size. Once the plants are larger & in rapid growth, you can jump up in size by maybe 2 sizes. Dont baby them so much, they're plants. Just let them grow for a while.