Beautiful results! I loved reading your comments as you progressed. I feel every bit of your frustration with that piece and know exactly how satisfying it was to finish it with such fabulous results.
We had similar issues. I finished that one as well and it is sitting with a few other tigers who are waiting for a few more to be finished so they can all be a quilt together. I have to say I found that pattern poorly designed. The fabric provided was 18 ct but the pattern called for a couple of colors with 3 strands and 1 (at least) with 5 strands. I quickly decided 5 was not going to cut it and backed down to no more than 3. The charting for the back stitching was indeed hard to decipher. I'm not a fan of the Dimensions kits in general. They tend to use a pale green ink that is hard to see on the patterns themselves, their back stitching indicators are very poor (a "thin" blue line and then a slightly thicker blue line of the same shade - and you're supposed to suss out which is which on the chart) they give you poor quality fabric, and they seem to make up thread colors so even using a conversion chart, you have to remember to keep enough of a sample to match it when/if you run out. I've had 2 kits of theirs where I've run out of thread, and I didn't have to frog and I'm not a wasteful stitcher.
Don't give up on back stitching. Many other designers are much better with their indicators and it's not nearly so frustrating. Back stitching isn't my favorite, but I feel it often tends to give cleaner lines to the finished product.
Happy stitching and congratulations again. It really is beautiful.