Could you briefly explain how these plans differ?
Here is the product description from our Sweet Spot Marathon Plan:
This plan is built for epic races with a foundation of Sweet Spot and Threshold work to make sure you’re ready for 10-30 minute climbs during a 50-100-mile event. We structure this plan with structured training during the week, and “freestyle” workouts on the weekends to keep your mind fresh and having fun.
This plan was featured in [ Outside Magazine, hit this link to read all about it! ]
(https://www.outsideonline.com/2235501/what-i-learned-sweet-spot-training)
Here is the product description from the 100 mile plan:
This six week 100 mile mountain bike race plan will prep you for a grueling 100 mile mountain bike race with gobs of Sweet Spot and Threshold plus a dab of anaerobic work during the week. The weekends are full of long rides up to 8 hours with plenty of climbing that will give you a chance to test your fueling plans as well as your saddle fit! There’s also plenty of low aerobic endurance work to help you build that mitochondrial density that will make you more efficient on race day.
Over the course of the six week training plan you’ll ramp up your hours up steadily to handle the long day in the saddle. We’ve included some of our favorite workouts (Bursts, Sweet Spot, Criss-Cross & more) to help you prepare for a great race day!
In Summary - choose one or the other depending if you are training for a ~ 50 mile Marathon Race or an ultra 100 miler , like Leadville.
Hope that helps!
Frank,
Sounds like the 100 is higher volume. Is the taper similar? I would be using this as the last 6 weeks before NUE 100mi races. My average finish times in the past are 8-9 hrs.
Thanks
For 100 mile NUE races for 
do the 100 mile training plan, good luck and don’t skip on your simulation rides!