I assume you are familiar with the REPLACE function, with which one can easily change the _X0020_ back to a space?

If you are asking about how to avoid the issue...

Do you believe this to be a detailed and thorough response to...

The biggest benefit I can think of is that this method provides total control over how changes get deployed, rather than relying on SSDT's schema-differencing and updating tech, which is...

Can you explain the logic behind this requirement, please?

I cannot see any questions in your post. What, specifically, do you need help with?

Can you provide some sample code which we can cut & paste into SSMS?

Microsoft Excel,...

Easiest way is probably to use Brent Ozar's PasteThePlan. Instructions here. Once you've done that, post the link here.

Still can't get pass this error:

Type conversion in expression (CONVERT(int,[d2].[attValue],0)) may affect "CardinalityEstimate" in query plan choice, The query memory grant detected "ExcessiveGrant", which may impact the reliability. Grant...

I second everything Brian Gale has posted here. Excellent advice.

Another possibility is pushing the contents of the table to a text file on the remote server, zipping that, copy to local server, unzip and import.

As implied in the previous...

Perhaps try modifying your Master package to spawn only four copies of GetNextTable?

Given that it bombed out at 4GB before, it's a bit strange how it only made it to...

As the package is held in encrypted form in SSISDB, I expect this to be quite difficult to achieve.

I'm not quite understanding the sequence of events.

Does the code you have...

OK, maybe this will help. Try adding the following 5 lines of code outside and after the first Using block:

...
       ...

I don't know how to fix things using your current top-down package hierarchy, though I do know that there used to be a memory leak in FOR loops years ago...