I have not played the Morgan but I own a Spanky MKII. It is a phenomenal amp. It gets plenty loud with solid clean headroom for a 15-20 watt amp. The Eminence GA-SC64 is a great speaker and with some (A)NOS tubes in V1 & V2, the Spanky MKII is brilliant. The Mids control really helps with dialing in some Tweed-ish dirt or for thickening up the Blackface-ish cleans. The Hybrid Master is very versatile and allows you to get some great preamp gain tones at lower volume levels. The Mids & Hybrid Master really make this amp flexible. With single coils guitars, the Spanky MKII is only capable of low gain overdrive/pushed/dirty tones. But with humbuckers, it definitely starts to break up more.
The reverb is also really nice as it is very subtle up until 12:00, then it gets splashier, but still nowhere near what my '65 PRRI could do on 4. When I compared the Spanky MKII to my '65 PRRI (with a GA10-SC64), the core tones were very similar, as the Spanky MKII could be dialed in to sound just like the Princeton. When pushed into overdrive, the Spanky was smoother & less spikey than the PRRI. The PRRI did have tighter bass with the 10" speaker, but the Spanky MKII definitely has a fuller, wider spread due to the 12" speaker.
Overall I think that the Wooly Coats Spanky MKII is a phenomenal amp. It fully satisfied my "Princeton on steroids" amp search. I think this amp is vastly underrated and am surprised that more TGPers haven't gravitated toward it.