My plan and profile is 50 scale and my site plan is 100. The network labels are adjusted in my model and plan/profile so that they are not overlapping any of the text or other imprtant items. But since the text is huge in my site plan it overlaps almost everything.
For different scale drawings (layouts) I generally have a different drawing. X-ref the "base" drawing into it, and data shortcut the pipes into it. That way I can adjust the labels per drawing.
If you want the lables the same size regardless of the drawing scale you can create child styles with a smaller text size, and have 2 labels per pipe. I have not gone to that extreme, but instead I have tricked the labels into thinking they are the same scale. I scale the border in the layout, and have the vport the same scale as the other plan. I plot so the actual plot is the right scale.
Maybe in more modern versions you can set the annotation scale for the vport? Can someone with a later version respond to that part? (I am using 2008)
make sure your viewport is unlock. right click on it and select properties. In your properties dialog box set the annotation scale to 50 or 100 which ever you want. Then also set your standard scale to the same scale. When you are done, lock your viewport.
Tony Carcamo CAD Manager www.tonyscivil3dworld.blogspot.com