Best way to condense music into smallest amount of pages?

Maybe your printer driver has the ability to print two Pages on One. Further you could set the quality setting of the print to "draft". Duplex Printing is another chance to save paper...Many ideas...

You wrote:
I don't care about readability...
and later:
having all the music ... being legible.

To me, those statements have opposite meanings.

To obtain readability, you increase the scaling to more of a 'thumbnail' size.

I would adjust the spacing in between the staff's. Right click on a part or measure and select "staff properties". A table will pop up, and there should be a line where it says "spacing above staff" or something. I would decrease that number to make the staffs closer together (probably to like -3.00 or 4.00 but it can vary depending on the lowest and highest notes on each clefs. Once you got that adjusted, you can also go to page layout and adjust the spacing in between staffs as well. Back to the staff properties, for minor or repeated parts, you can also make that staff or parr smaller to scale so that it takes up less space. To get of empty rests or measures, right click in the measure with rests, click measure properties. You'll see parts numbered 1 to however many number of staffs you have in a vertical column for that measure. There should be a box that you can select or unselect to make that Part visible for that particular measure, so you're able to select specific measures of a Parrt that you don't want to be visible and which measures of that part you still want to be seen...