Suggestions for working with denim:

If you have a problem with bulk in the denim, raid your tool box and bring out the hammer!
I have one with a regular head with a small handle which is perfect - you have better control with a shorter handle. My husband found it a tool shop (he can't remember which one, it was 22 years ago!) Try a big box reno store.
Whenever you need to stitch over multiple layers of denim, like a seam, pound the area to be stitched with your hammer - about 3 blows for each spot usually works for me. The hammer will flatten down and relax the fibres in the denim and make it much easier to sew.
Make sure you have a solid surface to pound on - DON'T do this on your Grandma's antique Duncan Phyfe table!
If you do this on your sewing machine, you will eventually pound the paint right off - don't recommend this either.
A small piece of patio stone, or a block of hard wood works well.
Remember, you aren't making flax, don't beat it to a pulp. Perhaps try it on some scraps to get the feel for it.

Make yourself a Hump Jumper:
Find a double-stitched seam - an inner leg seam is perfect. Cut a strip about 6" long and 1½" - 1¾' wide with the seam running down one side, Fold it so that the finished size will be about 4" X 1½". Half will be single thickness and half will be double thickness. Hammer the fold about 3 times in each spot. Stitch down the seam side, (be sure to back stitch), stitch across the short side, and up the other double side. Before you get to the fold, tuck in a cord of some sort at the corner (a spare boot lace would work), stitch it closed and backstitch to secure everything. If you like, you can serge the 2 cut edges to keep fraying to a minimum. I wouldn't suggest serging the seam side - a regular household serger won't be able to handle the bulk, you might bend the fingers in the serger. ($Ouch! been there, done that, won't do it again.)

Now you can hang your Hump Jumper close to your machine. I have several made for the different weights of denim. I keep all of the Hump Jumpers on a large key ring under the right front foot of my sewing machine. They are always right there and I can't accidentally discard one. If I don't need them, I can hang them by the ring out of the way and they stay together. The wide width beside the seam gives you enough fabric that you can maneuver the Hump Jumper easily - this is a cheap and easy gadget to make. If you find you need it wider or narrower, it's a simple thing to make another one.

Using your Hump Jumper:
When you have to go over a seam, reach for your handy, dandy Hump Jumper.
Just as your pressure foot starts to lift on the seam, stop with the needle in the fabric, lift the pressure foot, tuck the Hump Jumper in behind your foot with the original jean seam under the back of the foot, lower the foot down again and the foot will be level - if your pressure foot isn't level, try the other end of your Hump Jumper. Now you can stitch perfectly across the seam. Often you don't need it coming off the seam, but if you find you have skipped stitches after the seam, you need to stop with the needle down when the toe of your foot just tips down at the front, lift the foot and put your Hump Jumper, seam side, under the foot on the one side only and set the pressure foot down onto the denim with the needle right beside the Humper Jumper. I usually put it on the right side of the foot. This way you can stitch off the seam without running over your Hump Jumper. When the pressure foot is clear of the seam, lift the foot, remove the Hump Jumper, lower your foot and carry on.
As long as your pressure foot is level, your machine will stitch properly. When the pressure foot is tipped up or down, you will frequently have skipped stitches.

Hope this helps.
After putting all this down and editing it, you seem to have made amazing progress! Bravo!
Program the coffee-maker to brew another pot in a few hours and keep at it!
Keep your camera handy to record your progress so we can all learn from your experience. We're cheering you on!
Looking forward to seeing your denim kilt!