Creating huge documents using "Metres" as document unit

[Rob123456789]

I want to use Designer to design a layout for my garden. The garden is about 8 meters wide by 15 meters long.

Is there any problems with creating a document so big? I am not planning on exporting it to a raster image - and can leave the default resolution at 72ppi.

Would it be better to set my document to 8 x 15 cm and just divide all my measurements by 100? So that 1m becomes 1cm in the document? I just don't want to get so far in and find that performance becomes sluggish.

[GarryP]

The document unit of measure (UOM) is largely irrelevant to the ‘weight’ of the document (size in memory and/or disk).
For example, a document with a UOM of pixels containing a 1000×1000 pixel image with be the same ‘weight’ as another document containing the same image but with a UOM of metres.
It’s the content of the document that matters when it comes to the ‘size/weight’ of the document, not its dimensions or DPI (unless you want to print/export it).
In your case, as far as I can tell from what you have said, the UOM won’t make any difference and you should be able to use metres without any problems.