Keep in mind I have a TCS. I'm running 10" front springs and 14" rear springs. All my spring perches are all the way down. My ride height is a bit higher than I would like but it's not objectionable (and certainly not worth the cost of four new springs at least at the moment). Of course, my only adjustment would be to make the ride height higher which I don't want and that is my only complaint with these springs.
My advice would be to get 8" front springs and 12" rear springs so that you'd be able to have some adjustment. As I say, Keep in mind I have a TCS. IIRC, up to some year (through type 54?) the ride height had not been bastardized for headlight height requirements.
You didn't mention spring rates... That is a whole 'nother conversation. I will say I have tried 250F/130R and did not find it terribly harsh. I'm running 160F/115R now and I find it pretty comfortable. I tried another set but I don't remember them off hand. And then there is the stock rates (truth be told there are all manner of rate combinations you might want). Nobody ever complained about the handling of a Europa with stock springs. The 160/115 I'm running now feel good to me and a bit more relaxing than the 250/130 I've run in the past but were not as stiff as they sound. I think if I change anything from here, I'd keep the same rate and get shorter springs.
Since there is no further description for SJ046D0004 other than S1 and S2 spring, I expect that is the stock spring with the stock rate. There are lots of places in the US where you can order springs by length, rate, and diameter if you want something other than stock (hint: search for something like "1.88 inch racing coil over springs").
