Fixed object positioning

Im currently trialing ReadyMag and one slighting annoying thing that’s holding me back from buying is an issue im having around fixing objects. Say I have a single page (no scrolling) and just want to align the image bottom right 50px either size. I guess in HTML it would be absolute positioning rather than fixed.

The issue is that although the published project will be fullscreen I want to toggle between fullscreen and actual dartboard size when designing.
However, when doing this with a fixed object it doesn’t scale with it and remains off the artboard. I understand why this is happening - its fixed to the exact position, but it does mean I have to realign everything. Or I need to unfix before changing the scale.

I may not be explaining this very well but essentially I just want to control the absolute position of an object 50px Bottom / Right irrespective of whether I am in actual size or fullscreen.

Is there something I am missing here? It feels like it would be a very straightforward feature to just specify the absolute position rather than be confined to only fixed.

Any help would be appreciated!