You don't need to train everyone. You just need to train your attackers and GK. That's enough.
If you tank this early and increase you overall team quality you will fall into money spenders bracket, avoid it.
Have team quality around 100-110 percent with 7-8 star attackers and a good GK.
And if you need green boosters and you are this much dedicated then you can use the booster farming technique everyone uses. Start with your normal playing eleven in a friendly match and as the match starts substitute your playing eleven with your subs. This way your main 11 players won't lose condition and your subs would be able to play even if their condition is below the required condition to play.
If someone gets injured then don't heal them, simply sell them and go to the market and buy a 3 star player for 1T.