What are your specific problems? I find Devcon 5 Minute brand very versitile. The proportions are not critical and I can even lower the viscosity of the by adding a little lacquer thinner to the mix. In addition, I really like to take advantage of its characteristic of wicking its way into material to form a deep solid bond and of smoothing over rough surfaces on streamer heads. Yet another neat feature, not my idea, is to lash down thin plastic eyes onto streamer heads with fine monofilament and then covering them with epoxy. The monofilament wraps will then become invisable.
You can even make opaque colored mixes by adding non-waxy powdered artists pastel chalks that don't chemically react with the epoxy.
From my experience, I don't buy anything but the smallest size tubes because I seem to always make sticky messes when storing the the stuff between uses.
The only negative for me is the yellowing over time.