In your opinion, which title carries more credibility for a pre-sales technical role?

If the pre sales involves more of standard product / platform demos answering FAQ's. a solutions engineer would be suitable. If it involves fine tuning the solution presentation for the client nuances and suggest more advisory kind discussion, an architect might be suitable

Just like the results indicate, these titles are pretty interchangeable and I don't think that from an outside perspective either one will make a prospect take notice more than the other.  This is the person building the solution to fit...