3D FlipBook - Trouble with preload and asking about customize arrows

Thank you for the plugin, it is great

But I have two questions

1) I have some troubles with preload pages. The pdf is 8 MB and has 46 pages but the preload pages not working, I mean it loads the first one but it does not load the next ones until I click to see the next one. My configuration is: preloadPages = 10 and the rest of the properties are in auto mode. I try with another configuration but the result was the same

2) Can I customize the arrows? I mean for example smaller when it is showing on mobile phones.

Thank you in advance