Current bike has a 1" steerer tube with a shim to allow use of a 1 1/8" stem (currently installed).

50mm worth of 1" spacers below the stem.

1 1/8" top cap.

Once I find my sweet spot I will have the steerer tube cut but for now if I want to lower the bars by moving spacers from below to above the stem, should I use the original 1" top cap or the current 1 1/8" top cap?

Just trying to make sure my bars don't come flying off at an inopportune moment!

Thanks in advance!