Orienting objects on the bed  

Orienting objects on the bed

So I'm waiting for my MK3 kit, which will be the first 3D printer I've yet owned. I've been learning Fusion 360 to use as my primary CAD program. A friend who has a MK2 suggested using Astroprint, which I have not yet learned much about.

While learning Fusion 360, I started with a video by a presenter who asked us to change the axis orientation so that the Z axis is up. So I went ahead and did that, and created some simple designs with that orientation.

However, I then decided that I preferred the videos by another presenter, who has his Fusion 360 set to Y up, so I changed mine back to that. Now I have some designs in that orientation. However, I notice that when I open my older designs, they still display with the Z axis up.

Here's my question. When I get to the stage where I'm actually preparing one of these designs to send to the MK3, am I going to need to worry about whether the orientation will create any problems with the object being well-located on the printer bed? If so, where is this usually tweaked? In the CAD program, in Astroprint, or in a setting on the printer? Is there anything good to read about this particular topic?