Don't do it. Common bermuda grows vertically way faster than hybrid bermuda. You would have weird patches of taller grass amongst your 419. If you are mowing 419 correctly, common would not do very well either. 1/2" or lower HOC is hard on common.
They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety.
Benjamin Franklin 1775
Sell not virtue to purchase wealth, nor Liberty to purchase power.
Benjamin Franklin Poor Richard's Almanac1738