Neither.
What's causing the flats?
Are the holes on the tread side or the rim side?
Index the tires to the valve stem so that you can line up the punctures with the tire and the rim.
Analyze each flat until you know what caused it. This can be done after the ride.
Heavy tires will make your bike feel sluggish.
Have you tried higher pressure? 90# doesn't seem like enough for a 25 mm road tire.