You’re wise to take this year as chance to build more base. You can never have too much. If the 8 week plan went well the 24 week plan is a good step up. It utilizes all the longer term progressions explained in TftNA book that are not possible in the short 8 week plan you have used. I think you’d see the results you are seeking with the 24 week mountaineering plan. It’s our most popular plan.