>>Hi,
>> Is it possible to set TMPFILES path programmactically?
>>
>>Thank you
>
>No. It must be set in your configuration file. A good way to do this, and avoid possible problems is to generate the file in a post setup executable that's installed in the same directory as the application.

An alternative is a launcher, which can construct a custom CONFIG.FPW based on what it finds prior to starting the actual app - it can identify which drive is most eligible for use for temporary storage, and then start the app pointed at a specific CONFIG.FPW using the -C command line modifier.