Good comments Pistoff,
I think the excerpt added by OldGoat addresses your point very well. If the excerpt is taken from The Time is at Hand as noted, then by Russel's own admission "...we disagree with Mr. Miller's interpretations and deductions, on almost every point," is confirmation of his knowledge of Miller's position. If he had simply used the term "interpretations" then I would not think it so clear cut, but to include "deductions" and the expression "on almost every point" indicates a clear understanding of his writings.
Thank you for posting this OldGoat. I think it clarifies the point well.
It is obvious that he did not accept Miller. It is also quite apparent that he was shallow and deceptive. He took his audience for fools and his audacity to state "We have been unable to secure Mr. Miller's writings to compare his interpretations" and then write the excerpt noted above makes him an unrealiable and inauthentic just like the stuff he touted as truth.