hi danalyticz, 

while i don't have a build manual in front of me, i have built three 17 LTs over the days and there is nothing that sounds manifestly wrong about what you are describing.

the beam on the 17 LT is 23 inches so the spreader may be a tad long in that the panels are 4 mm thick and you would subtract 8 mm (four from each side) or about 5/16 inch so your spreader should be more like 22 and 11/16 if you were being very precise.

that said, i would start stitching it and i think you will find it all pulls together nicely. if you still have a bulge or something unusual once you start pulling it into shape, then snap a picture and write us another note.

fwiw, it does not naturally 'pop' into the corrext shape until you stitch the side panels to the bottom panels...so its very hard to evaluate where you are going to be until the stitching starts.

of course, you can also double check your bottom - to ensure you stitched the keel line to the keel line....and the side panels.... to ensure you have the front and back appropriately oriented.    mistakes like that, while not common, happen every now and then.

let us know how it goes, 

h