Many years ago, I wrote the following information for users of a particular brand of tyre:-
http://www.avonmotorsport.com/resour...re/user-advice
I no longer work for them because I didn't want the insane amount of travel; much as I loved it, it's not compatible with a young family if they are not also married to petrol.
I can't claim to be the world's greatest tyre expert, anyone who says that probably hasn't a clue about even the parameters of what such a person should actually know, but I've been around a fair bit and was a single seater tyre engineer for over ten years (working with several people here in the process).
There are several subjects involved here and I can't touch on them all, but bluntly, the fastest a tyre will ever be will be when it's new. But you have to have it at the right pressure and know that it's balanced, it must be fitted to a car that presents iteself at the optimum ride height and then when that tyre's done, it's done.
Most people want more mileage out of a set (here at least, I suspect Alonso for example, with whom I worked in F3000 can afford to fling tyres at a car should the regulations allow). They run cross-plies, crew for themselves, may even fit the tyres themselves and always want the most miles on a race weekend. All of these things point toward a scrubbing in procedure that reduces the risk of hitting the track and having something not quite what you want.
Scrubbing in lets you KNOW that the pressure is correct, assures you that the balance is correct, stabilises the volatiles in the compound and breaks the very weak links in the cross-chain matrix, leaving a more stable presentation to the road, the only part that means anything. Please bear in mind that when I say pressure, I care not for what you set them at cold, becuase if you're doing it right, the tyre won't be cold when it's near the circuit. Hot pressure is all that matters, and you need to research all the elements that come together to effect that hot pressure. Maybe your tyre brand absorbs water? Do you need to purge them? Veryify that all the water has come out? After all, they've been sitting in a warehouse / trailer / outhouse / garage for who knows how long. Water vapour screws your tyre pressure more than anything else you can think of. Are you certain that it's all gone?
Please note, not always, but largely, there is very rarely anything at all used to release slick tyres from moulds, mould release is a pain and best avoided. Race rubber is very rich in oils, it leaches from the second it's made and softer compounds are obviously worse.
Why do FSAE teams run for specific cycles? Usually, because they can repeat the process and that makes for a logical sequence.
Ah, I could go on for a lifetime and still not explain everything, not least becuase I don't know everything (hardly anything, some may say).