Marathon Plus's on Sun RhynoLites and Sun CR-18 rims are tight.
I change mine out to the Marathon Winters every winter just to remind me. I've broken a couple of sets of cheap plastic levers, I now use the Lezyne Aluminum ones from VO. They are a bit short (you might want to wear gloves, but you can put as much pressure as you want on them without worrying about breakage - the downside, is that they scratch up the rim edge. I suspect the big steel lever from ParK would be easier, but still scratch up the rim.