I wouldn't use 5200 (rjxj). This stuff is used mostly as a marine "bedding" to seal penetrations thru fiberglass ( thru hull fittings, etc.). It cannot be removed without taking some of the surface material with it.
Silicone doesn't hold up to UV Rays well, thus it's not widely used in marine applications.
Everyone I've spoken with recommends Dicor. Self leveling for the roof. Non leveling on vertical applications.
As a commercial contractor we use sikaflex products quite a bit, but I'm not familiar with specific products. It must be decent stuff. It gets spec'd a lot on many types of applications in the building trades.