Hi Dan, I recently used Perfect Resize tile function to check color and edge detail (prior to printing) of a couple 64 x 64 inch canvases which were produced from measly 1.4mb jpegs.
I ran the tile feature as a separate step after a series of de-noise, enlarge, sharpen cycles to produce 9 files of 22x22 inch tiles that, when combined on a wall, would/should theoretically resemble a printout of the entire 64x64 piece if it were printed untiled.
I would be using a new roll of 64 inch wide canvas for final output, I profiled it with a Colormunki, but hadn't used for production before.
To proof/check, I chose to print only 2 of the 22x22 inch tiles on matte paper of the areas which the client explained were critical for color and detail. I'd bring the 2 printed tiles to the client and after 2 rounds of changes was able to get approval based on the tiles. I printed the single 1.1GB file in Lightroom onto the 64 wide canvas-- turned out great, colors and detail were surprisingly close, considering the differences in Enhanced Matte and canvas.
Anyways, my point is that it may be useful for you to run the tile function again, on one of your 3 large tiles, in order to check or get an idea of how any part of the 3 large panels will actually look in real size, especially if the media you are printing on is new or somewhat different to that which you commonly use. This way you won't have to commit to printing a single large 33x98 tile to find out you need to make some changes. It helped me get over the anxiety just prior to clicking the 'Print/ok" button...