GT3Pure Theme – problem with BLOG options

Hi guys!
I have 2 questions about a BLOG on PURE theme.

1. on PURE DEMO site, the sneak-peaks of the blog posts (fullwight type) are short – there are just about 8 lines of text, and posts are arranged at equal intervals ( https://www.gt3themes.com/wordpress-themes/pure/blog-fullwidth/). meanwhile on my site, there are very long text lines before the “read more” button apears, and posts aren’t arranged egualy (https://www.lazowska.com/blog/). can anyone please tell me where can I set the lenght of posts sneak-peak?

2. I also have trouble with changing the blog type from fullwight to grid. I tried to change it in my admin pannel at the “sites” section (I have a Polish language version so I’m not sure if it’s a right name)with a GT3 page builder and “blog box” but it does’t work.,
I also tried to change it directly in post edit – on the right there’s a “custom layout” box but I have only fullwight type and “yes” or “no”option, and even if I select “no” it doesn’t change to grid type. Where can I change the whole blog type from fullwight to this: https://www.gt3themes.com/wordpress-themes/pure/sample-page/?

I’ll be very thankful for your help!

Ann