If your pitch is from a kit in the last few years, it is probably the right viscosity for the average user. When making the lap, make sure that the squares are off center in relation to the tool. Make more than less if possible and just push them in while the lap is still hot and use plenty of cerium oxide and a drop or more of dishwashing detergent in the water that you use. The 1/3 stroke will be good for a start but watch the progress and just as soon as most of the mirror is polished out, do a Foucalt test to verify the shape of the mirror and it's always wise to start checking the figure from that point. You will get used to doing the test before it becomes critical and thus you won't be as lost when it comes to figuring the mirror. The only real way that you can mess up your mirror permanently is to drop it. All others is just a little more work.