Well my experience with towling is this:
We felt sorry for, therefor - purchased a completely untame cockatiel. He was wild! Hissing, biting, flapping all over his cage and absolutely would NOT sit on our finger for a split second. And when he bit, he drew blood, no "testing" for him!
We gave him a few weeks in his cage, just talking to him, offering him treats..which he would NOT even consider taking and putting our hand in his cage and just holding it there...he'd stay in the corner, shaking...and if we moved our hand, he'd hiss and lunge his head in an attempt to bite.
After several weeks, I felt like absolutely NO progress was being made with him, so I opted for a more direct route. I put a cushion in our bathtub, brought our tiel and his cage in the bathroom, toweled him out, shut the shower curtain, sat down on my cushion and let him loose. He was clipped so he couldn't do much, and being in the bathtub, he couldn't get away either. I kept my finger under the towel so I could tollerate any bites without reacting and I worked with him until I felt we'd made progress with him stepping up on my finger.
I did the same thing the next day, and the next.
We made quick progress and by the 3rd day, although I had to towel him OUT of the cage and back IN the cage, once he was out, he was happy to perch on my finger and let me talk to him.
After the 3rd day of toweling, I'd always offer up my finger 1st to get him out of the cage, if he reacted poorly, I just toweled him without a fuss, got him out and went about having "happy time" out of his cage. I still had to towel him to get him back in his cage too at this point.
I started letting him walk about on my bed with our other tiel, I'd lay down a big towel and sprinkle "treats" on it for them to forrage and he LOVED that!
Within a couple weeks time, he happily jumped up on my finger and let me take him out of his cage without toweling, I still had to towel him to get him back IN his cage, because as soon as I'd get close to his cage, he'd fly off and climb up on it and get all defensive when I'd try to get him on my finger. So I'd towel him, no fuss, and put him in his cage.
It's been a total of 3 months that we've owned him...he does not need the towel EVER, he absolutely loves to come out of his cage, go back in his cage, sit on our fingers, arms or shoulders. He talks up a storm now and is developing quite the vocabulary. He's a very very very happy bird. Now we are slowly working with him being touched and scritched...that I have more patience for as we are building the trust and Chicken Little, just this week started preening my husband and I...before-he'd just sit with us not moving...LOL!
I think if I didn't towel him, we'd still be in the "let me put my hand in your cage" phase with him maybe staying on his perch instead of cramming himself in the corner scared to death. I don't have THAT kind of patience so I went with a more direct approach and I'm glad I did.
In my profile page is a picture of my son holding both our tiels...Chicken Little is the gray pied whom this post is about.

As you'll see by his pictures, he's quite a content little guy
I think toweling can be a very effective and efficient way to train a bird if used correctly and for the right reasons. I think if it's working for you, then keep doing it, and my advice to you is when you feel ready...try first without the towel...and if your bird doesn't respond they way you are hoping, then, don't make a fuss, don't get upset, don't keep trying to push the issue to the point of being annoying...just towel and move on.

So if you have your bird on your finger and you go to scritch or pet and he or she bites, hisses and or flys off...then go towel, do your scritching/petting what ever for a few minutes, then be done..until next time where you try first without the towel...
Hope that makes sense.
Good Luck!
Toni