Multicriteria objective functions are really hard to get right. Weighting features from 10 to 1 is actually a decent first approach- it should separate good solutions from bad solutions- but if you're down to narrow differences of the weighted objective function, it's typically time to hand off to a human decision-maker, or spend a lot of time considering tradeoffs to elicit the weights. (Thankfully, a first pass should show you what features you need to value carefully and which features you can ignore.)