How does Mass affect rate of turn?
The second law of motion states that: $F = m * a$

Rate of turn will be determined by the acceleration: $\frac{F}{m} = a$

If your vertical lift is 10,000 lb, in a 30 degree bank, your lateral force is $10,000 * tan(30)$, your acceleration is $\frac{10000 * tan(30)}{10000}$, or $tan(30)$.

If your vertical lift is 9,000 lb, in a 30 degree bank, your lateral force is $9,000 * tan(30)$, your acceleration is $\frac{9000 * tan(30)}{9000}$, or $tan(30)$.

Thus you can see the rate of turn depends on the bank angle, not the mass.