I have a Queen Quilter 18 which is apparently a sister to the Tin Lizzy 18. Maybe an evil step-sister...not sure.
I had the same loopy issues on the bottom of all of my practice work when I first started.
http://tinlizzie18.com/images/TinLiz...ers_Manual.pdf
Not sure if this Owner's Manual came with your machine, but it has been a wonderful asset for me! My machine came with about an 8 page stapled together xerox copy of what they called an owners manual. I couldn't even tell how to properly thread my machine. My loopies were a result of the following problems.
1) I didn't have my machine properly threaded. Once I got everything working correctly, I have used a sharpie marker to indicate which direction thread needs to go through all of the loops. That way if my thread ever breaks, I don't need to pull out my owner's manual.
2) Had no clue what the tension release lever was! My original manual never mentioned what it was and why you have it. The lever needs to be in the "UP" position while threading, then in the "DOWN" position before you sew. If you are ready to sew, and the thread easily pulls through your needle, you need to re-thread your machine.
3) Adjust your upper tension. Unlike your DSM, you can turn the tension dial a full turn to adjust it just a little bit. If you have loops on the bottom, your upper tension is too loose. If you have loops on the top, your bottom tension is too loose.
4) Adjust your bobbin tension. With your thread bobbin properly loaded, it should slowly roll down if you hold up the end of the thread. If it falls straight to the floor, your bobbin tension is way too loose. This tension is adjusted with a small screw driver directly on the bobbin holder. (I also used my sharpie to mark which direction the bobbin thread should be going here as well.)
5) Make sure your tension release lever is lowered before you start to sew.
6) Adjust the level of your hopping foot. There should only be about enough space to fit a dime between your quilt and the hopping foot.
7) Lastly, make sure you don't have your quilt so taught in the frame. I like to only have my quilt backing pinned to my leader fabric on both poles. I float my batting and quilt top. I do use straight pins to pin all 3 layers together on the sides before I start to quilt.
Hope this helps! I was quite frustrated when I first started to use my LA as well.