Since you have already gotten the pistons of 0.25mm oversize and the wear(taper)on your cylinders is 0.020in(about 0.50mm)you won't be able bore your sleeves.You will have to put in new sleeves and have them bored to fit the new pistons you have. If you can get the dealer to exchange them,do so and get std. pistons. They should be somewhat cheaper. You will have still to install new liners(sleeves).
The angle of rotation refers to the additional torque you apply after you have torqued to the specified amount. Set your wrench to the 12 o'clock position and turn to the 3 o'clock position. It is used on the stretch bolts. You should measure those bolts to make sure they are within specs. Simple. Keep us posted on your progress,and have a Merry Christmas.
Bill Lewallen Lexington,Ky.