Regarding QR, that's not entirely correct... GOFF and Off are 2 different things. GOFF represents a 'guaranteed' minimum of 4 days off... that doesn't stop you bidding for extra which could be anything up to 6 days off in a row (given up to twice per month). The six days is normally published in the roster as 4 days GOFF + 2 days 'Off' or 6 days 'Off'. Anyway the detail is irrelevant.
Going back to spending 10-12 days in Sg. This could as previously mentioned be with all the leave - 42days or I've seen 2x6days Off being granted in the roster. It's all fleet and Rank dependent also... I would be surprised if a 320Capt could spend that much time at home (in any country) based on days Off alone unless he/she was going back at every opportunity e.g even if only 3days off or something.