After I posted the question I decided to go on a google mission to find the answer.
By the looks if it the process is relatively straight forward, the dust myth is just that (a myth) spread by data recovery companies to keep their stupid prices and 'trade secrets'. The platter moves at speeds we're familiar with (7.2k rpm being the most common), and with that speed it pretty much throws off any dust before the HDD has a real chance to start r/w.
From looking into it the biggest problem is if you actually need to move the platters as opposed to simply replacing the board as jp said, or putting it in a freezer to unlock the bearings. The main things you need (without getting into platter removal) are the right screwdrivers, a pair of latex gloves (finger oil is a bit different to dust), a place to ground yourself and a steady hand.
Makes you wonder how much money these recovery companies get away with before getting into a situation where they actually need to do real work (i.e. removing the needles, re-aligning them with the new platter etc). And even then they probably just say the data is unreachable and throw the money back at the customer.