Is there a way to add an Excel sheet (from template) to another Excel file in KNIME?

Dear KNIMErs,

I have an interesting problem. I am running a somewhat bigger data transformation workflow on the KNIME Business Hub using a data app.

In that workflow / data app I am using a lot of workflow invocation to keep the main workflow clean.

The very first Call Workflow Service node feeds into an Excel Cell Updater node (which basically takes the transformed data from the sub workflow and feeds it into a newly created file based on an Excel template.

Now exactly this Excel template is the problem: It has one sheet with 60,000 formula cells. This sheet is not touched by KNIME but so far has been part of the template file I use in the Excel Cell Updater node. This huge sheet drives the file size of the template up to 70MB which leads to a Java Heap Space error on the KBH.

Now I now that there are tricks and ways to convert Excel to a real XML file (the good old rename to zip > unpack workaround 😉) and yes, I know, I could do that. Why am I not doing this right away? Well, I need to handover this workflow to a client later, and this might be really hard to explain to them.

So my question is basically this: is there a more “native KNIME way” to do that?

Thank you in advance for your input.