Hmmmm....
For what it's worth, from my perspective of pilot streaming boards in circa 2000, it was all about what seats were available with little regard for ability and NO regard for personal preference.
My major strengths were formation and IF while my weakness was low-level nav. On streaming from EFT I asked for fast-jet, then multis and rotary a distant third. I was surprised to find myself at Shawbury a few months later! (With the last rotary navs in 2001 in response to an earlier query).
On role disposal I asked for Puma, then the last Wessex (I really wanted to experience NI), then Merlin, then Chinook (it just looked weird and unsafe), then Sea King a distant fifth. I was, again, surprised to find myself at Odiham a few months later (pattern forming here...)
On posting I didn't really care by that point. The posting ceremony was a bit tame though. You chug a pint and at the bottom was a coloured sticker: black for 7 Sqn, red for 18 and green for 27. I saw a green in mine which meant I was going to be a 'bunster'...but that got cancelled just before I left the OCF due to low-level nav bufoonery! (See para 2!)
Of interest the most fun role disposal I ever witnessed was at Valley while I was doing some pre-wings SAR training: the FJ students were tied to a back wall with a bungee while trying to reach the far wall where pictures of a GR1/F3/GR7/Jag/Hawk/Tucano (memory fails if there was a Canberra too) were pasted. The first one to grab a random picture took it to the QFI who looked at his list and handed the guy a pint of lager if it was the wrong guess (down it and try again sunshine) or a glass of champagne if correct!
I never saw a multis role disposal, but I just assumed it involved pies and ketchup-filled doughnuts...