We report combined soft and hard x-ray scattering studies of the electronic and lattice modulations associated with stripe order in La _1.875Ba_0.125CuO₄ and La_1.48Nd _0.4Sr_0.12CuO₄. We find that the amplitude of both the electronic modulation of the hole density and the strain modulation of the lattice is significantly larger in La_1.875Ba _0.125CuO₄ than in La_1.48Nd_0.4Sr _0.12CuO₄ and is also better correlated. The in-plane correlation lengths are isotropic in each case; for La_1.875Ba _0.125CuO₄, ξhole=255±5 Å, whereas for La_1.48Nd_0.4Sr_0.12CuO₄, ξhole=111±7 Å. We find that the modulations are temperature independent in La_1.875Ba_0.125CuO₄ in the low temperature tetragonal phase. In contrast, in La_1.48Nd _0.4Sr_0.12CuO₄, the amplitude grows smoothly from zero, beginning 13 K below the LTT phase transition. We speculate that the reduced average tilt angle in La_1.875Ba_0.125CuO ₄ results in reduced charge localization and incoherent pinning, leading to the longer correlation length and enhanced periodic modulation amplitude.