I do the same type of riding, and yes, the downtube battery definitely makes mounting the bike a bit difficult. In my case, the better weight distribution makes it worthwhile
Here are a few thoughts:
Make sure you secure the battery inside the tote so it won't slide around. You might also consider some form of protection to avoid damage from other items bouncing around inside the tote. Bike batteries are somewhat fragile, and can be dangerous when damaged.
Also consider the wiring. It needs to be 10 or 12 gauge stranded wire to handle current surges. Make sure it is properly fused, routed and firmly fastened where it won't get pinched, chaffed or caught on something. A short can be disastrous.
You may find the bike will be too light in front with all that weight so high, and that far to the rear. Make sure the braking, steering and balance aren't adversely affected.
Have you considered panniers? It looks like your rack has the necessary support rails. They carry the weight much lower, and greatly improve the center of gravity. I use them on very long rides to carry extra gear and even a third battery. When doing so, I put the battery in a padded, protective case in the event of an accident.
Unfortunately, aside from test riding one, I have no experience with Rize bikes. Hopefully, someone with more knowledge of that brand will offer better advice.