I spoke with masterbond and west system yesterday in regards to another aluminum project that I have. Here are the highlights.
Masterbond has a $700 minimum order and they advised that I look elsewhere.
West System was next on my list since I already use their 105 system. They told me that the 105 system has a holding power of 1100 psi over sanded aluminum. The number goes up to 1300 psi if you wet sand both sides of the joint with the epoxy in place (80-100 wet dry sandpaper). The epoxy serves as an oxygen shield. They said that they are suggesting the wet sand technique over the use of the 860 surface prep. I asked why and was told that the psi results are nearly identical and that they are having trouble meeting environmental requirements with the 860 so they cant sell it to every state.
The conversation shifted to their G flex epoxy. They said that wet sanded joints are resulting in a 2800psi joint. The product has a shelf life of years. They said that they have a test batch that is 9 years old and is still working like new. All of this resulted in an order of a 2 quart kit for $100 delivered from one of their online retailers. The tech suggested that I use the 655 Gflex which is thickened. The reason is more to do with the viscosity than the need for a filler in the joint. He said it can stay put even on vertical surfaces while the 610 would be impossible to control.
this does not really answer the question, but I hope that the information is helpful