The InDesign plugin works automatically with iPad resolutions. Thus we recommend the standard 1024x768px o 768x1024px, which are proportional to iPad. When exporting we have the option of specifying Retina resolution, which exports everything with a doubled resolution. However you will continue working in InDesign with the original resolution.
In the case of wanting to work with other resolutions, there is no problem. The only thing is, that when you create the document, you will have to establish the desired dimensions and the plugin will export it in that resolution. It is important to not mark the Retina check-box or the plugin will double the resolution.
We recommend that in the case of using another resolution, you carefully consider with which device you want the publication to fit perfectly. Always try to find the most standard resolutions. Nevertheless, our platform is open to whichever resolution you define.