It looks like that area is up at 63 Latitude so it will not be covered by the SRTM terrain awareness which goes up 60 degrees north.
In the absence of terrain awareness data the approach you have described would the be the correct way to do it. Good job, seriously.
Since the area is pretty big there really is only one way to handle this: bring your own terrain data.
There is likely a government source or terrain data available for that area. Get that and trim it appropriately.
Then you can upload it to Maps Made Easy for processing. Once that is done you can select it in Map Pilot Pro as shown here:
From there you would use it as you normally would with SRTM.
6 sq km is roughly 1500 acres. Your Pro subscription includes the processing of 1000 acres per 30 month. Elite includes 10,000.