Working with XamlRenderingBackgroundTask constraints

I'm still trying to get my head around introducing the XamlRenderingBackgroundTask for universal apps. I am currently planning the following application and I want it to have custom XAML bitmaps per tiles. Now I have a few questions about this:

All examples and guidelines recommend writing the XamlRenderingBackgroundTask in C ++. While I don't mind it at all, I still have a few problems accessing the functionality of the app when rendering a tile. For example. I want to get the latest updates from the server and calculate locally what I should show on the tile. The same functionality is used in a complete application and is written in C # and I think that implementing all the functionality in C ++ would be a lot of work (server communication, using SQLite and Linq). This example shows one implementation of XamlRenderingBackgroundTask, but it is rather limited in functionality as it only renders in time.

I thought of two possibilities for dealing with the constraints of the XamlRenderingBackgroundTask, and I wanted some opinions on what the best way would be:

• Create two background tasks, one in C # and one in C ++. A C # background task calculates the data to be used and stores it locally for a C ++ background task. Problem here: will there be memory / cpu quota limits here? How can I guarantee consistency (First C #, then C ++)?

• Store your C # logic in a WinRT component and reference it from a C ++ background task. I can't imagine this working because the C # component will load the CLR and I will click on memory limit.

Also I have another question regarding background tasks:

Are memory limits or 16MB limited on a 512MB RAM device, an upper limit that will never be exceeded? For example:.

I create an image and update a chunk that is 14MB. If I reset the tile structure to be correct and so on, do I have 16 MB to work with again, or just the remaining 2 MB?

I ask because I wanted to allow the user to connect multiple (secondary) fragments to the start screen. If I can only create one fragment, it can never update (with XAML images) other fragments.

I would be grateful for any thoughts on this matter.