I've also got a DIY rack that offers benefits along with challenges. When I lived in an older house with hardwood floors above a basement, I found that 3 2x4s in the basement below the rack bracing the hardwood above to the concrete floor below made a huge difference vs. the $10 cost. If you can do similar, just err on the long side when cutting the wood to fit and jam it in using a dead blow hammer...a good trick. Cheers,

Spencer