Most people who get a new board will be stuck when it comes to screwing on the foot straps. There are plenty of options to choose from but the correct one depends on our level and the conditions.
When you start with the foot straps I recommend putting them as far forward as possible. Since we are doing the transition from having our feet near the mast foot to putting the feet into the straps further back, we want to make the difference between these two stances as similar as possible.
Big boards (slow planing)
In the initial phases of windsurfing in the straps we will still be standing pretty upright even while planing. For this case it is good to have the straps pretty centred so as to keep the pressure into the board more over where most of the volume is. Planing slowly with the straps close to the rails will only sink the boards side and slow you down even more.
Big boards (fast planing)
As we pick up speed, the fin will start to act as a foil and begin to lift the board out of the water which then tilts downwind. If we have the feet in the foot straps close to the centre of the board we will not be able to avoid this. Therefore, as we begin to achieve high speeds consistently (and have the board lift up every now and then) we know we have to put the foot straps closer to the rail.
Just a small note here: when you get into the straps in this set up, try to do so before you start planing. The straps on the side will force out feet to be close to the water and it will happen every now and then that the heel catches the water. The faster you are going, the more it will trip you up and the more likely you will have a pretty little catapult.
Usually the small boards are used in choppy conditions or in waves. Personally I have always felt more control over the board with the straps closer to the centre in these situations. Especially when wave riding where you have to put pressure on the downwind rail while in the straps of the upwind rail.
For more control ver the board in general i recommend putting the straps further apart. This creates a large lever for us to control the board with our feet.
I hope this has given you a bit of a better insight as to where you want to put the foot straps. Naturally our body size and weight will have an impact on where we will feel most comfortable and in most control over our board so you will have to try out different options to see what works for you. However, these guidelines should give you a better idea of what you need to change instead of shooting in the dark. For more tips and tricks from Boardseeker Magazine and pro riders check out their page here.
Let me know how you get along in the comments or if there is any other observation you think should be included.