My prediction - without really knowing but hopefully an educated one - is that the A35 has enough power to drive the SCM19s. But as others have said, so much of this is dependent on listening volume. As always there is a loudness point where a system stops sounding good and you'll have to hear whether the volume you want is below that. But surely this setup ought to sound good?!?
Another factor is your preamp. I know nothing about the C-2420 but so much of what makes for a great preamp is a high-current output, which enables the power amp to work more efficiently. I am assuming based on Accuphase's reputation and the fact that the two amps should mate well, that this is the case. Class A watts are like dog's years and given that you have a nice preamp, I think you should be fine.
I do think the SCM19s are a poor choice, generally, for your amp given their low efficiency. They are hyper-accurate but their lowish efficiency may not give the dynamics that a SS class A amp is capable of going into a higher efficiency speaker. Though 85 db isn't that bad for a smallish speaker.
If your goal is to drive those speakers to their potential, and you have access to the domestic Chinese hifi market, then I have to ask: Why would you not buy a monster power amp from the best Chinese companies? What is the mainland price of, say, two top of the line JA-100 Jungson monoblocks? I am pretty sure you could buy these locally for less than $1000 USD. It's different for us, since we have to pay shipping, customs duty, etc. which doubles the cost, and then we've got a gray market product that nobody can support or repair. But if I lived in China and was operating in that ecosystem...much as I love British (and American, Danish, and Italian) hifi stuff, the fact remains that I'd have to spend 12x that amount of money get something that good from a British company. Just saying.