Can this be said?

Hi again.

-name-さん歌うのうまいよ
そしてギターを弾くにも上手と思います。

Is this correct? It doesn't feel right to me..
What I want to have said is something like
"I think you're good at singing/your singing voice is nice, and you're good at guitar aswell"
well, yeah. I think you understand what I mean. I also sometimes mix up the polite way of saying things with the more casual way, help?
ps. this doesn't have to be said in an overly polite way, though I would be thankful to see both versions and the differences!

(そして)ギターを弾くのも上手と思います。

informal
ｘｘｘさんは、歌もうまいし(いい声してるし）、ギターもうまいね。
polite/formal
ｘｘｘさんは、歌も上手だし、ギターも上手ですね。
ｘｘｘさんは、いい声してますね。又、、ギターも(ギターを弾くのも）上手ですね。

----ｘｘｘさんは、歌もうまいし(いい声してるし）、ギターもうまいね。---------

.....you're good at guitar aswell"----


。。。ギターもよくやれますね？