NXT Private Blockchain Testing Kit -- Change block times?

I see there is the NXT Testing Kit for us testers:


Is there a way to change the block times to 5-10s on this NXT test kit?

I believe I found the line for the block time change for NXT clone starter kit, but @riker says its not as simple as just changing those 2 lines. What else do I need to change to make it work?