HDF5 has an excellent documentation, and both packages are specifically designed to provide a clear an solid interface to the caller, so working with such libraries allows the programmer to focus directly towards efficiency and optimization, what when it comes to scientific data (not to say in the astronomical domain) is undoubtedly an essential property of every piece of code.
Having worked for many years in the graphical representation of empirical data with C++ in scientific and technical domains, we are best placed to understand the requirements of a large-scale multidimensional data format, as well as its different approaches in order to better suit different types of datasets, and so we would be able to find quickly our way into your current application in order to extend it in a solid and modular way without compromising its current features. We could also be helpful for the representation of charts, and even for the customization of specific tools inside these open-source packages.
We have been working with Visual Studio and the MSC compiler since its very beginnings, so we could easily keep on the implementation any coding conventions and structural rules you want your program to grow with.
Regards
The Bramfeld Team