I look at bike fit as being the single most important feature of any bike; far and away more important than, say, frame material, weight or equipment. I bring a tape measure to any bike purchase and take those measurements home on put them on a CAD drawing. From there I can see the required stem and seatpost to get a good fit. (I even wrote a program years ago where I could enter the numbers from brochures to get that info.)
Now, I got a lucky break 40 years ago. The mechanic at the shop I worked in convinced me to buy last year's Fuji Pro as my racing bike, I did. It fit like a dream and I saw radical improvement from the very first ride. That has been the basis of all my rides since. But what I quickly learned when i started addressing good fit was that nearly all production bikes require (for me) enormously long stems and often have poor weight balance between the wheels. (I wrote that program to whittle down the titanium bikes to ones that might be worth a test ride. It opened my eyes. I found no production ti bikes that wouldn't require custom stems. $4000 for a "class B" fit? No thinks. The ti bike went on hold until I landed "the job". Ordered a custom as soon as I knew it was going to pan out.
To your plight - I"d consider the Cannondales both "class B" fits. I'd look at another bike. (The smaller one with new stem and maybe seatpost might be a keeper. And since you are relatively new to this fit game, a smaller bike has the advantage that there are fewer restraints to the key parts of the fit - saddle and handlebar location - since larger stems and posts can always be obtained. Even custom posts and stems are far cheaper than new bikes.)
Don't settle for less. A bike to get it figured out is OK, but don't stop until you have the bike that really fits.
Ben