I feel more confident that this is a better system for (lazily

I only purchased a single dog tug line and harness for Sky. My son seemed hurt that I didn't also purchase a harness for Sirius. My thoughts are to start out with Sky and see how it goes. If it goes well, I may then add Sirius to run beside me with a hands free leashing system. (There were times that I hooked both dogs up to the bike at the same time. This resulted in a ride that quickly attained speeds beyond my comfort level. Although, I may have been okay with the higher speeds had I felt more comfortable with the set up in general.)
I am actually kind of torn between having Sirius run beside on a hands free leash, or getting a harness for her (if the set up works well with Sky) and letting them take turns pulling the scooter. (If she pulls while running beside, it could throw off my balance as well as add to the speed.) I think I will likely try the hands free running beside first just to see how she is with the scooter. One thing I read said scootering was not recommended for timid dogs, since Sirius has fear issues, I'm not sure how she would react to having a scooter behind her. I woulnt' want her to panic and try to run away from it. She was okay with running beside the bike. Of course, if I feel super confident and comfortable with the scooter set up and ready to try speed riding I could hook both dogs up at the same time and I feel that Sirius would be fine running beside Sky.
Has anybody else tried scootering? Does anybody see anything glaringly crazy in my thought process?