A front pannier that's too big may contact the downtube during turns. One that's too high and too heavy may adversely affect the handling of the bike.
The mounting systems are the same, so any pannier should "fit" any rack. You should be able to determine how a given pannier will fit your bike by measuring; Arkel provides "blueprints" on their site.
A lowrider centers the pannier vertically on the axle. Using the blueprint you should be able to measure how far back the pannier will extend, and (also taking into account its thickness) determine whether it will provide sufficient toe clearance or cause problems during turns.
If at all possible, I'd recommend staying with lowrider front racks. On a long tour, the reduced stability of too much weight too high in front can be very fatiguing, if not hazardous.
Even with lowriders, you don't want too much weight in front, which is another reason to stay with smaller front panniers.
RichC
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Training: 2002 Fuji Roubaix Pro (105 triple)
Commuting/Daytripping: 2001 Airborne Carpe Diem (Ultegra/XTR, touring wheels)
Commuting/Touring: 2000 Novara Randonee (Sora/Tiagra/LX, fenders, lights)