bestchange.com is fairly good website, but you may also want to consider orangefren.com. It supposed only to show exchange which support amount you enter. For example,
1. If i enter i want to convert 0.0001 BTC (about $9.53) to LTC, it only shows 6 exchange.
2. If i enter i want to convert 0.1 BTC to LTC, it shows 19 exchange.
But make sure orangefren data is accurate (both exchange rate and minimum exchange/deposit amount).