I think that you refer to scrolling that is a little different than usual. Other programs (all mapping apps, web browser, image viewer) move the contents with pointer movement on screen. Since pointer location is not refreshed that often on N900 I decided to go the other way to provide smooth scrolling.

I do not want to talk math here but I can say that implementing two strategies for scrolling (usual scrolling and the one which is in CloudGPS right now - the "gliding one") will be rather easy. I will add an option for that once the onscreen settings are there. I personally prefer the current gliding strategy but I think the usual one should be the default.

It is really up to you. One should consider the number of tiles to download and needed detail level. I never do bulk downloading but sometimes I explore the places I am about to go to using CloudGPS. I almost always walk on my feet so my preferred zoom level is 17 or 18. For the road between start and end of trip I do not need much detail because I only use CloudGPS to check the route progress. Zoom level 9-10 is often enough for me.

Yes, please. It is a great idea. Wiki page will be appropriate place to store project info. You can start creating a page template and I will fill the missing bits in next couple of days.