When you get the teak off you might find that the plastic angle they used is all worn and broken, I used 1/8" angle you can get from any hardware store as a replacement. But you will have to make the teak grove deeper for the extra thickness.

I used a length of corner used in vinyl siding...much thinner than metal angle and slides great...it comes shaped to wrap the corner of the house and you cut away the angle you need...stuff is TOUGH as nails and might be easier to cut and work with than metal, depending on your skills and tools...and you won't have to cut the teak away to open up the groove... :party: