you want to keep your LDT multiplier at 3x. 250x3 is 750, you want to keep it under 1000. And i wouldnt bump up the multi to 11x. Just raise the HTT, you get more performance that way.
you ask how? Its just random settings that pop into my head. nothing too difficult. 3-3-3-8 are pretty relaxed timings for RAM. 250 HTT any A64 should handle. 10x multi is very common. 1.55V max recommended voltage on air.