Do you think the same strategy should be used for low and high buy in tournaments?

I usually play the same way but of course I get more apprehensive about high values, can this influence the game?

How high is high buy-ins tournaments?

In general, just as in cash games, it is best to bet more for value with made hands and bluff less on lower levels/stakes. But that can change if you identify some nitty players that you can steal a lot o pots off.

The higher you play - the more balanced you should be against the population. And at the lower levels you can often identify how you can change from a balanced approach to an exploitative one quicker and against which players. As stated that is often more value heavy betting, but not always.

I also had a lot of doubt but ended up taking, playing in smaller tournaments some moves and bluffs do not go through there are many more players who will always want to see cards (flop).

Good question, like to know the general consensus on that one myself.
I would assume that the same strategy would work if it worked at all. I would also thing lower value games you may get more callers, then again players in high value games are bolder. It may take some twicking.

Definitely you should play in different styles because on low buy-ins tournament people are crazy to call you with ace high or to call 3-bet with T8 suited. You should wait your moment and crush them because they are convinced that high pair is nuts.
This is not like this on high level buy-ins tournaments.

No, you need to adapt to the players at whatever level. Usually at higher levels they wont open shove AJo for 300 bbs, but in a freeroll that is common place, you just have to adapt.