I Only run club racing and I am cheap so I like to start my tires at about 48mm (mine come at 50 and I like to get them round by my standards so it takes a little bit to get them the way I like) For the rears and the Fronts I just deglaze the surface.

Now I do get chunking and I have a lot of old tires that when I get some free time I just cut off the rims with an exacto knife and put into Zip top bags labelled with their compound.

So when it comes time to fix a tire I have lots of bits to use and contact cement them onto the tire and re-true it to a uniform size and then I do the fronts to about 2-4 mm smaller than the rears but I also chunk the fronts too so the same applies.

I have been known to test different compounds together too like pink/magenta or Yellow/black and even Magenta/black Just too see what effect mixing compounds on the outer edge (like 1cm tops) does to traction and chunking

our track changes with temperature and I like to have 2-3 different kinds of tire just incase.