Just something to think about. I'm normally the lightest rider on our rides at about 135lbs. If I'm riding up front with a 180lb guy on rolling terrain, we sometimes have difficulties not half wheeling each other. You understand the issue on rollers - I'm faster on the uphill at constant power while he's faster on the downhill using constant power. So we each have to adjust to each other a bit. It works out just fine but we both have to pay attention. But I'll be honest, I like pulling with a similar sized rider as things are just easier.