I've done a lot of intricate lay ups with epoxy resin and different types of fiberglass using tight weaves, satin weaves, volan finished and silane finished cloth. There are some sites that say Silanes are better for epoxy than Volan. Looking at real test data by one of the biggest and best quality fiberglass weavers indicates that Silane finished fiberglass cloth laminates do have a couple percentage points better properties. In reality if one one needs the cloth to conform my experience has been that the volan finished cloth has always been softer than the silane finished cloth given the same style. I saw one fiberglass cloth seller that indicated that Silanes were more moisture resistant. I would have to agree just based on the fact that silanes are put on the cloth in an aqueous bath. The theory would be that any exposure to moisture would just drive the reaction further. I keep all cloth sealed in plastic and just don't leave anything sitting out and have never really done any tests but would say under normal conditions free of moisture and sunlight both are completely stable. The main criteria would be clarity and conformability. If you need the cloth to be clear then the choice would be silanes and if you don't need clarity but conformity is the most important then Volan is the choice. On this page I will provide photos of samples of different styles with different finishes to show conformity.
Here are photos of style 7725 fiberglass cloth showing conformibilty with varying finishes. The assumption would be that once wet out with resin the cloth would stay in place more than just dry as seen here. 7725 is an 8.5 oz/sq yd 2x2 twill that uses the yarn ECG 75 1/0 in the warp and ECH 25 1/0 in the fill. The thread count given is 54 x 18 but in reality is 18 x 18 ends/inch. There are 3 of the ECG 75 1/0 together in the warp laying next to each other and not
twisted to differentiate this from three twisted yarn as would be in ECG 75 1/3.