Yes, it is a good strategy, but don't take money from the redraw for the investment. Get a LOC on the equity in the property and use this for the investment property deposit. If you use the offset money the non deductible interest will increase.
What you propose is not a good strategy because if you use your offset aaccount money for an investment your non deductible interest will go up. Think about it - this could cost you thousands of $$$ a year for 30 years...