I'm still convinced that the quality and evenness of my rim tape application (it's hard to find tape that precisely matches the size of the rim well) and the fit of my valve stem are the key determinants of how airtight my setup is. Most issues I have had have been solved by being a little bit more generous with the sealant; I keep the bike indoors with central heating so drying sealant can be a problem.
To the poster with the uneven diameter and centreline deviation - can you take it up to the pressure limit to try and get it seated and then drop it back down? And check your rim tape position? I would expect these issues in handmade tyres but for a tyre to come out of a mould uneven seems astonishingly unlikely. Failing that I'd just ride it and see if it works it's way to the edge.
Discuss light weight issues concerning road bikes & parts.