I have Yacugar progressive springs and I use 15W oil though I think 10W was just that little better (it greatly depends on the oil you use, I use Silkolene RSF Pro, it's synthetic.) I will put the 10W in next time again as I was happiest with that. The Yacugar springs are stiff, more so than the Wirth ones, but not overly so. They are great, but I'm a almost too lightweight for them at 12 stone. They are lovely 2 up and I'd wager someone of your weight would be happy with them solo (not that I'm not, I like solid suspension.) I was going to go for the Wirth ones, but I had problems getting hold of them so went with the Yacugar ones in stead as I got a good deal at the time. I thought the Hagon ones were too soft, judging by the figures I got from Hagon. They were barely higher rated than stock ones, BUT they would be much better quality than the stock ones and won't degrade like the stock ones did (they put the cheapest ones in as stock to keep costs down.) So I guess what I am saying is that if you can get a good price on Hagon ones, go for it as it will be a major improvement and you probably won't notice much difference between them and the higher priced ones. If you search the Oily Rag section for a thread called "DL650 Suspension" then you'll find a thread where I document all my antics about upgrading the front and rear suspension on my Wee. Once you've done the front you'll notice how sad the rear is, a Hyperpro spring for the rear is the cheapest way to sort that