Adjusting Bullet Power

I was also thinking something similar, adjusting the bullet power (in regular surfing) to maximise the overlap of the waves and thus the size of bullet shadows. My biggest objection is that I wouldn't be able to use the x.x5 rounding bug to my advantage. The other problem was that it would also make the enemy capable of figuring out where I fired based on where the overlap was biggest.

I'm surprised it didn't work for you. Maybe if you simulate firing a tick later instead you will get better overlap? If your bullet power is significantly less than theirs you also get lower gunheat, so you have a few ticks to spare where you can choose when to fire.