The newest Big Boy will come with either the Big Boy tender or the Challenger tender depending on sku. The Big Boy tender already has a wide roller spacing, so it doesn't have the issue on the Atlas #5 switch. I've now had the Challenger design revised to open the roller spacing so it won't have this issue when the Big Boy ships.
Thanks for pointing this out. As mentioned here previously, we cannot design for every other manufacturer's track system, but I will always be open to these comments so that designs are modified to try to keep everyone happy.