Assuming the crit chance and attack rate from Iketh are correct, we can approximate the damage done by the Valks as:
1750 * (1 + 0.5 * 0.026) = 1773 damage, average per attack (counting crits)
16.6 * 1773 = 29.4k damage on proc
And, using the 1% proc rate, we can calculate the approximate dps of the proc.
(1 / 1.0) * 0.01 * 29.4k = 294 dps, when casting every 1.0 sec
(1 / 1.5) * 0.01 * 29.4k = 196 dps, when casting every 1.5 sec
(1 / 2.0) * 0.01 * 29.4k = 147 dps, when casting every 2.0 sec