I don't see any "show stoppers" with your application. 20-30 instances of a packed Perl program with Tk sounds reasonable. Of course the program will start faster if you have Perl and the modules that it needs installed because this eliminates the "unpack the .exe" step. However in my experience the users will be tolerant of a couple of seconds startup time, above 3 secs and you will get bitching (or at least I do).

The last time I did any SQLite benchmarking, I was using an old XP laptop as my development machine. I could get maybe a dozen transactions per second. And about 50K inserts per second (as single transaction). Your server machine is undoubtedly faster than that. In your case to initialize the inventory table, run all of the inserts as a single transaction. A million row commit is just fine with SQLite. The write commit process has a lot of bookkeeping to do, but there isn't much difference between a single row commit and a 10K row commit. Each one of your writes to table 2 in operational mode will be a transaction. So max write rate is probably less than a couple of dozen per second, but even if you just get 10 per second, that is probably fine. Sounds like each user will be doing a fair amount of thinking before making a manual comment.

Sounds like you have a fine SQLite application.