Double to single chainring nut spacer

I got a Shimano FC-5603 triple crankset on which I want to install a single chainring for a 1x drivetrain.

The stock chainring nut + bolts fix the two larger chainrings (a double) to the crankset. The granny gear is fixed with just bolts into the tapped crankset.

However, I didn't want to modify the stock chainring nut + bolts or buy new ones, so I made these spacers that take up the width ordinarily consumed by the second of the two chainrings.

We'll see if the plastic creep will thin out the spacers over time.