New site on 7.1; header padding on tablet, and font size and line height in mob nav menu

Site URL: https://caterpillar-cylinder-38cp.squarespace.com/

Building a new site not yet live (or paying) but now seem to know my way around the basic settings. I will need to custom code but had hoped it could be avoided (I have past experience albeit rusty in html5 and css3). 

There are two immediate design issues but likely related so I've put in one post. All are reported to customer support who say they've passed it on to the dev team and pass me on here. So hope someone can help me please!

(1) The header viewed on tablet (ipad mini 4&5) has too much padding top and bottom, it's disproportionate. But it's ok in desktop and mobile. Is there a way to address this in coding or is it too advanced  for £15/month pay plan?

Might the problem be that I started with a blank page for home page rather than a designer page? Actually I started with a designer page but then duplicated it to get rid of the designer images from the portfolio pages. 

Changed it to white to make it 'look' better, but included the blue-green original in images below (all ipad mini 5).

(2)The mobile header nav menu has disproportionate font size, so much so I think it's not coded for. Both mob and tablet (iphone SE2&5s; ipad mini 4&5).

Line-height on tablet is awry. Wrapped lines merge. It can be adjusted in the header mobile options, but then screws the mobile version, which is bearable. I believe it also affects the desktop Title name (ie Robin Paris) line-height. So the choice is to have tablet... wrapped nav menu names with slight space between ascender and descender, but mob too spaced and desktop altered too.

In main panel design settings, line-height is set in ems but font size in rems. So imho there's an imbalance there to start with.

I have seen other websites with similar huge font and merging wrapped line text, but can't find anything about this in the forum. 
 

Hoping someone can help, please. Is it a start again on designer site or something known? Site entry with golithafalls2 btw.

Thanks in advance,

Robin