PorkChop, it sounds to me like nembutsu is doing exactly the right thing by illuminating the calculating mind instead of letting it run unchecked.
I remember reading that one of the revolutionary things about Shinran was he didn't stress specific practices anymore (like 30,000 recitations of the Name every day) but the attitude behind them, the faith. Literal or figurative to me seem like more kinds of practices.
As for being born in the Pure Land, my calculating mind (maybe like yours) remains a bit agnostic about what happens at death. But the extent of Other-Power and Amida's inexplicable grace provides a bright backdrop that lights up the temporariness and smallness of my own thoughts and opinions. In this way, the ideas we take for granted are pointed out for our benefit. Patience with the process has been very important for me. We experience this mind continually, so death is merely changing scenery. It seems to me birth in the Pure Land is something experienced in some form of "now", whether the one we know here, or the one we guess about at death. I try to remain very watchful for Other-Power everywhere for that reason.