MAIN MENU CHANGES

Good morning,
I have installed joomla 3.4. My URL is
www.new.qualitaweb.es

I have several questions:
(1) Currently the thickness of the menu is 80px. How I can change this size to 70px? Does the text of menu to spend 80px-> 70px is perfectly distributed?

(2) Originally, this template has two (left and right) menus, How could not remove one of the two menus in order to make it a classic menu? How it would be done so that the logo quedase located at the beginning of the menu?

Appreciate details in the explanations. Thank you very much for his trouble.

Hi,
topic #1:

#gkHeaderNav.active {
height: 70px;
}
.gkMenu > ul > li, .gkMenu > ul > li > a {
height: 70px;
line-height: 70px;
}

topic #2:
Try:

#gkHeaderNav #gkLogoSmall {left: 0;}
#gkMainMenuLeft {
float: left;
padding-left: 220px;
width: 99%;
}

#gkMainMenu {text-align: left;}
#gkMainMenuRight {display: none; }

So as I result only Left menu will be used.

Thank you for the answers given. However, it remains to solve one small detail about the first question.

I have already given in the CSS code "Custom CSS code". If you enter the website, you can see that on the home page all goes correctly, but if you enter one of the options from the main menu (for example, "Quienes somos"), the menu returns to be 80px, and when down in the page (we move through the page) passes 70px. How can you solve?

Thank you so much for the solution given, and for the trouble taken. Thank you.

Opsss I forgot to copy you one more line:

#gkHeaderNav {height: 70px; }

I saw in your portfolio few projects based on YT templates

Mi intención es usar, a medida que aprenda a manejarlas, las plantillas de GK. Tengo muchas otras dudas de esta plantilla, para poder usarla con mis clientes.
Muchisimas gracias por todo. Eres un crack. Un fuerte abrazo.