I'm registering my new Navionics+ card. Need some advice

I purchased a fishfinder that included a Navionics+ card recently (Helix 5 DI GPS). I just logged in to the Navionics website and I was going to register my card (they say you have 60 days to do this after purchase, although I'm not sure how they know when I purchased?)

In any event, I've installed everything and am at the stage where I am dragging a big square across the screen to choose my Sonar CHarts for download. (Community Edits are not available to Helix 5 DI GPS so I'm just downloading Sonar)

Here are my questions:

1. how much am I allowed to download? The card is 8 GB and has 5.7 GB of nautical charts for US/Canada preloaded. Does that mean I have the other 2.2 or so GB available for SonarChart data?

2. Should I keep the nautical charts or should I purge it all and then just re-download the nautical charts in say Ontario or Florida where i might actually use them, thus will that allow me more room to download SonarCharts? i.e. if the answer to 1. is YES

3. Am I able to do this in a couple of downloads, or do I only get one shot at it? i.e. can I do an area now, and then do another area later? Or does it all have to be one big square that you drag out, rather than 2 squares, say 1 for Ontario and 1 for Florida?


Basically that's what I'm trying to figure out. Any tips would be appreciated.

Thanks

I can't answer your first two questions, but I can answer the 3rd.

I too just installed Navionics+ on my Dragonfly and you CAN update in small chunks at a time, rather than all at once.