  We perform optimization of Q-factor in the system of freestanding
three/four/five/six coaxial subwavelength dielectric disks over all scales.
Each parameter contributes almost one order of magnitude of the Q-factor due to
multiple avoided crossings of resonances to give totally the unprecedented
values for the Q-factors: $6.6\cdot10^4$ for the three, $4.8\cdot10^6$ for
four, $8.5\cdot10^7$ for five and one billion for six freestanding silicon
disks. By multipole analysis of the resulting hybridized resonant mode we
observe that such extremely large values of the $Q$-factor are attributed to
strong redistribution of radiation that originates from almost exact
destructive interference of dominating complex multipole radiation amplitudes.
