I actually sometimes like the slightly kaleidoscopic effect generated by similar scale patterns together (yes it's a clash, but if done deliberately and well, that can be fun too), but in that case, I would think going the whole hog with a patterned square as well would sell the intent better. As it is, the square is very sober, and so demands a bit of sobriety elsewhere too. A solid shirt would probably do that, by separting the relatively similar-scaled jacket & tie.
Thanks HF...this is spot on...and the reason i love teh forums. Ill try a solid blue next time..and the time after that..a patterned square.