I had to play around a bit to understand the Streak rules. To clarify:
Once you lower the center bank, if you finish CHEESE using only the center ramp, then you earn the streak bonus of up to 600k, 100k * number of letters earned on the center ramp. This is only earned when CHEESE is completed. It’s not timed. If the center ramp is open and you earn a CHEESE letter elsewhere (left ramp, right ramp, or right target), you forfeit the Streak Bonus.
The one change I would make from the Hard install is to change Ad.35 BUILD MILLION from HARD to MEDIUM. The HARD setting makes the Million arrows unlight when you hit them, and this isn’t fun when combined with the Streak/Cheese motor bank settings, IMHO. INDISC had this set to Medium too. BTW, the manual lists the options for this as “Easy, Medium, Hard, Ex. Hard”, but it’s actually “Ex. Easy, Easy, Medium, Hard”.