What troops should I have? T1, T3, T5?

That‘s a very easy to answer question: if you have knowledge for t5, you should have t5. If you don‘t, they are just risk for you as they might be weaker then enemies lower level troops... 

So first thing to check is, are you really using the troops (type or level) you are most developed in?

In military

In Troops I-V

Troops I-V gives a lot of influence and can be done very cheap in gold on the higher levels (level 11ff)

That also means, that a lot of 300 mio influence player might just have developed this area. Therefore this influence might come from full level 3 knowledge and is not very developed in other skills, which can make you much stronger if your military knowledge is also developed. ;)

The „Golden Rule" of the game is, that you don‘t have more then 10%-15% of your influence in troops. For one simple reason: if you get killed - and you will get killed someday as everyone does ;)) - you loose it all and it will hurt you and the kingdom and the clan, depending on what event is on. Also if you have a lot of troops, you look stronger then you are and probably get attacked by stronger player. E.g. you have 3 bn of inf whereas 1 bn is troops. your enemy has just 200m influence out of troops, so who would win the attack? ;)

I have about 3 Mio t1 Melee in, which are my mainly used troop type. 1 Mio t1 scout and killer also. Then I focus pretty much on level 3 troops where I hold a few more million and around 1 Mio of T4, as I have them fully developed - unfortunately not the t5 yet :)