You probably wouldn't run into rpm related harmonics problems with your installation, but you can when running single springs at elevated rpm levels.

Little brother runs a 500 cid DRCE engine in his 8.13 second Henry J drag racer.
Rpms are 6800 at launch and 9200 rpm when shifted. (4-speed Lenco.)

He ran single springs for a while and every run he broke one.

The breakage quit after he went to dual springs.
The inner spring - whether round wire or flat spring stock - act as vibration dampers and keep the main - outer - spring from doing weird things harmonics-wise and self destructing.