How do I decrease the spacing between the site-title and site-description

Well, if your website url would work, we could help you better.

https://avantgardeophthalmicplastics.com

Just use css.
There are many ways, one is with negative margin:
.site-title {
margin-bottom: -25px;
}

Great. It worked. Thanks a lot.

Another quick one…..

How to I increase the height of the Site title to 111px. Presently it is at 70px.

.site-title {
height:111px;
}

or, looking at your site, try:

.site-title a img {
max-height:l10px!important;
}