With a 160 or 161 (trade your Apollo), and your 9.7 and at 75kg, you should able to pump on plane in 7 to 9 knots with good technique. Less if you are in salt water. With a 10.5 or 11.0 sail, you could plane in 6-8 knots. The Apollo won't give you much more than that.
However with the 160 (which I have), your top end speed can be significant. I am 62 years old, weigh 80kg and have hit 28 knots on my 160 with a 9.2 Maui Sails TR3. The Apollo will hit the wall WELL below that.
On the other hand, if the Apollo is your only board, then a smaller board in the 100 - 125 liter range may be a better fit. For several years, I jumped from my formula board down to a 105 liter bump and jump board. However, I just bought a new iSonic 111 to fill the gap, expecting to use 6.5, 7.5 & 8.5 sails with it.
Your skill level should play a role in your selection, so some additional info. may be helpful.