1.7 should clear fine. I ran them with a B303 and it was a beast. My buddy has the car now. Still using the same 1.7 rockers and an x303 cam, but with aftermarket aluminum heads (60cc chamber). If the heads will be off anyway, it's always good practice to measure for piston-to-valve clearance. All it takes is time and a dollar's worth of play-dough.
The stock stamped rockers aren't good for performance. I don't like them. I've seen them break and I believe they can flex. A good brand of aftermarket roller rockers is money well spent. If you haven't purchased a cam yet, it's better to stick with 1.6 rockers. If you want more lift, select a different cam. That's just best practice. The 1.7's cause a little more stress on the fulcrum point. They're really a workaround for someone wanting more cam without having to change a cam. Having said that, you shouldn't have issues with 1.7's if that's the route you take. Again, stick with a good brand of rockers. Not a place you want to try and save $50!