Please give me your opinion about this compination.
Too much or it will be ok?

This will be fine, a Four Stroke is very good at keeping airspeed equal to engine speed. Much more than a Two Stroke. Have fun!!

I have a Saito .65 on My 40 size trainer.. I Love it. It will hang on the prop just about forever!! It is really a handfull but you can slow it down to a crawl!!

LATER

I jad a Nextar with a .52 4-stroke. It flew very well. It probably could have used just a little more power though. I think your .70 will be a great combination.

Thank for your answers.
I would like to use the engine after my training.
I would like a only four stroke
I think that with a bigger engine in the future i will heve more choices.
But i don't know what engine to choose.
OS 52fs
Os 72FS
Saito 82a
I don't know.

I've had good luck with my Saito .82 after it was broke in. It seemed to take a bit longer than some of the two strokes I've owned, but now is very reliable and powerful. But any four stoke .70 and above will serve you well in a second airplane.

By far the Saito .82. You will not be dissapointed!

LATER
PS. There are lots of other planes the 82 will go in with great results!

agreed the saito 82 is lighter and puts out more power that the os 70 surpass. saito 82 is my choice

It depends what your next model will be...... I would suggest a 90size model with Saito 100. It will be a bigger model to fly, to see it flying, better handling and more to the real thing. However if you plan to stay in 60size planes then the Saito 82 is the best match...