Maximun Manual Cache size question

[donet 7]

Where I live my internet connection data allowance is small and expensive and not real fast so I can't stay online for long to keep streaming data and so I'm looking to manually cache scenery.
I am curious to know what the manual cache size would be for different areas.  I realize that the size would be determined by whether low, medium or high was used and I'm only looking for an approximation.    For example an area of about 7,500 sqare miles using medium resolution overall and with the main citys and airports at high, what would be the total size in GB?   
I like to fly GA aircraft at about 5000' up to 200 miles.
Say I did a flight from Seattle down to Portland in the Pacific Northwest, a flight of around 100 miles that when manually cached covered about 7,500 square miles.  Or a flight from Sydney Australia to Canberra on a path about 75 miles wide with both airports on high.  Can anyone have at a guess as to how large that manual cache would be for that or any other similar area/flight?  Storage size on my SSD is not a problem.

[Nyxx 6,993]

I think when you select the area and the res it tells you how much it will use.

[donet 7]

Thanks David,
I did realize that but I'm looking to buy a new computer for the purpose and I hoped to hear from other users as to their experience with the manual caching so I can evaluate if I can cache a size big enough to suit the way I would like to use MSFS 2020 before I spend up.