I reviewed the specifications and data sheet for that product and it looks like their recommendation is sound. It is neutral cure, and has good environmental exposure specs.
Let us know how it works out. I still have a full bag (a couple of hundred) of those plugs but I must admit that I get tired of timing them to length and installing them as they only last about 5 years. I do believe that it is important to prevent water intrusion into those holes. The stainless screws, aluminum track and mild steel backing plates is a bad combination when water gets between those metals.
All the best,
Gary S. Silver
Amel SM 2000 #335