Regarding the logo text size, please try to check in the following path, if it is for Signature skin:
thtmlb_styles -> Page Fragments -> sap_skins -> nova
thtmlb_stand.css
search with th-l-sap-logo-text, it might look like
.th-l-sap-logo-text {
color: #8A95A2;
font-family: Arial Black;
font-size: large;
letter-spacing: -1px;
margin-left: -1px;
white-space: nowrap;
}