You have a beautiful and well thought out system. Your 301 motor unit has been pristinely restored. I could re-read this thread from beginning to end to find out for myself but I will just ask-where did you source it? I am guessing Woodsong or Classic Hi-Fi UK.
I am bit puzzled that you have a 301 motor unit and a 401 platter. To the best of my knowledge no 301 model was ever produced with a strobe lamp installed and only at some point after the 401 was introduced was a strobed platter offered as an option with a 301 during a short period in which both were in production, but again, without any strobe light retro-fit option. This is a minor detail of no significance; my own grease-bearing 301 has been Frankensteined with an aftermarket heavy duty bearing and a Dobbins platter as mentioned by me earlier in this thread.
I will again warn you that mounting the 3P is a very difficult proposition if you have no prior experience. Why such an advanced engineer as Vindmantas Triukas would provide such a misleading mounting template with his arms is a mystery. I mounted my second 3P myself but I had to remount it a second time, moving the arm base slightly forward to get into the zone where a typical cartridge could be mounted at optimal overhang. The integral headshells offer rather short cart mounting slots which only aggravates the situation. In this respect that I agree that having rotating leaf type mounting shelves is nice, but at the expense of esthetics, stability, and freedom from unwanted resonance.
And I will again highly recommend that you look into an outboard power supply designed for induction motors to smooth out the motor operation.