LV Plan + Rides, or MV Plan and Substitute?

I asked this question in someone else’s thread, so I’m sure it’s gotten lost. Starting with the time change in a couple of weeks, I’m going to be doing weekday rides on the trainer using TR, then weekend rides outside as the weather allows. Stats:

  1. 58 year old male living in NE Texas.
  2. I do two centuries per year, one in July and one 4 weeks later in August.
  3. I generally ride ~6 days per week total, taking Fridays as a regular off day. My current TSS is 600-700 per week.
  4. November until the time changes in Spring I will be riding Mon-Thurs on trainer, Sat-Sun outdoors as possible
  5. In Spring, I will be on trainer Mon and Wed nights with Tues, Thurs outdoors typically riding 25-30 miles at just under Sweetspot. Saturdays will be progressively longer days still just under Sweetspot until I hit the first Century in July and plateauing until the end of August, when we begin to ease up. Sundays are usually 25-30 miles at Endurance-Tempo pace.
  6. Total time on bike weekly is 10-12 hours in warmer weather, it usually drops to 7-8 hours per week in winter.

I’m looking at using the planner with my two major events as an A and B events, doing the Gran Fondo Plan with Sweetspot, Build, and Specialty. I really want to add the structured training, but I’m not sure how to work it in. My outdoor rides are part of a small group and it would be really hard to meet consistent numbers. We’re usually at Sweetspot for me on the total average power, but it’s not consistent. The only time I exceed sweetspot is on the few hills we have, which are short and not very steep (think overpasses). Should I go with the low volume and hope I can meet the demands, or should I go with the medium volume and substitute outdoor rides for workouts? Any help would be appreciated!

I’ve went with a MV plan myself and if weekend rides happen I drop the TR sessions.