After reading all the discouragements here about TiVo and YouTube, I have settled on a few work-arounds.
I manage YouTube from my computer, selecting subscriptions, playlists, ... I clear the lists online as soon as I've watched the program, before adding anything else, have learned that since I've set it to display newest first that if I add a series or sequence I should add it backwards, learned to clear subscriptions on my computer and add what I want to see to Favorites.
Now the TiVo displayed navigating arrows work, yes slowly, but they do work, sometimes I get the choice to vote an item up or down (the last one in the queue I think). TiVo/YouTube wants to sequentially play everything in the Favorites list, so keeping the list cleared of all items I'm finished with is working.
As well, it's taken me a while to negotiate YouTube on line, and I've got this working adequately. I wouldn't have even known where to start if it hadn't been for all the help and complaints here.