Hello,
You can change the video speed to slower using YouTube settings to watch in detail every action we did on that video http://prntscr.com/tel5i1 So, you can control the speed.
Using size option in the Logo settings you can control the size of the logo inside the columns it was placed. If you want to increase the size you need also to check the number of columns that your logo takes https://gyazo.com/9bd526de7b86caf4e437ed644eb9f359 For example, if you placed the logo in 2 columns it won’t be larger than 2 columns width (16.6% of the header width). To make it larger stretch logo element to 3-4-5 etc columns. So, logo size is not the only “frontend for the backend code”. Logo width just depends on 2 factors: size in the Logo element settings + columns number that logo is placed in.
Let me know if you need any other detailed explanation.
Regards