The only time I looked up Knopfler's tone it was a Komet amp, and I loved that sound so much I bought one. But I don't know of another that sounds quite like that Ken Fischer design (one of his last, possibly his very last). But now that you've asked, and knowing S-Gear to a decent degree, I think I'd start with the Wayfarer. From it, I've been able to get some of that syrupy thickness present in Mark's lead sound. If I come across a preset that's in the ballpark I'll mention it.
Edit: much of that tone is in Mark's fingers, so experiment with your technique as well.