Jobst Brandt (in his book
"The Bicycle Wheel" recommended for folks seriously interested in how bicycle wheels work) addressed the issue of the rim holes not allowing the nipples to swivel enough. He suggested bending the spoke so that the nipple beds properly in the frame, but there is no residual bending stress in the spoke. If you have bending stress, you have the possibility of stress reversal and premature fatigue failure. See pic below.
Sapim makes PolyAx(R) nipples that claim to have a wider range of alignment. Might help - haven't used them, but some folks here swear by them.
Strongly agree with OneIsAllYouNeed (at least on the OP's topic - clearly you need more than one!) regarding butted spokes. Butted spokes allow the spoke to stretch more, and when the rim is deflected, the spoke remains stressed over a wider range. There is no stress reversal. In the other direction, if the spoke is stretched more, the spring force of the butted spoke is lower and doesn't transmit the high force to the nipple or j-bend that a straight gauge spoke would.
Or, find a rim that allows more spoke swivel.
