You are running your system about the same amount of time that I do. I have all tubes from start to finish. Unless you are disabled I assume that much of the time your system is running your listening is on a casual basis, i.e. your not sitting in the sweet spot just listening. In this same situation I added a small tube integrated (35wt) and took a line out from the pre-amp tape loop out. I use seperate speaker cable and banana plugs and interchange the main system and the integrated depending on what I intend to do. Interestingly I find that the main system now only operates about 15 hours a week and I'm not obsessed with the deterioration of the tubes in my main system.
I have in the past used a SS integrated in the same configuration, which makes it even simpler, and cheaper.
I have in the past used a SS integrated in the same configuration, which makes it even simpler, and cheaper.