Canexel Siding?

I am planning to side with Canexel over my origanal cedar siding. We moved into the home 2 years ago and the sidng was not taken care of and suffered accordingly. It is weathjer beaten. I want to Tyvek and strap with true one inch pine on top. The cedar siding runs perpendicular and is lap jointed. Where some of the joints have curled up I noticed there is no sheathing underneath. I want to strap into the studs for assured strength and I am wondering if they make stud finders that will locate studs through the sidng.I can locate some from inside and transfer outside but I don't have A LOT OF FAITH on the studs being on the correct centers. Do they make a stud finder that will will work from oustside?