Normal dragon, how many stars?

I hardly worked in the past few month and evolved 100s of baby dragons, now I have many 6* and getting 7*s soon.
5* skills on every 10 turn hits very small and 6* not only every 25 turn but also hits only ~15K, therefore, my dragons are not my favorite 5* and 6* and I use other cards more unless I am low in CP.
The leader skill also useless.
Now, I need another 1-2 month to make them 7* and maybe 4-5 months! to make them 8*.
I double checked and 6*, 7* and 8* all have level III skills, so I wonder how much 7* and 8* will hit when fully strengthened?
I don't want to spend huge time and energy and create 7* and 8* cards that I don't use.
If anybody knows please let me know.
Also, with the new styr cards, if you level-up their skills, so a 8* can hit every 9 turn, can they become as good as a panzer at level 1 skill?
5* skills on every 10 turn hits very small and 6* not only every 25 turn but also hits only ~15K, therefore, my dragons are not my favorite 5* and 6* and I use other cards more unless I am low in CP.
The leader skill also useless.
Now, I need another 1-2 month to make them 7* and maybe 4-5 months! to make them 8*.
I double checked and 6*, 7* and 8* all have level III skills, so I wonder how much 7* and 8* will hit when fully strengthened?
I don't want to spend huge time and energy and create 7* and 8* cards that I don't use.
If anybody knows please let me know.
Also, with the new styr cards, if you level-up their skills, so a 8* can hit every 9 turn, can they become as good as a panzer at level 1 skill?