I desperately need to buy a de-matting tool for Sam since his coat is so thick. I can't decide which would be best, so looking for opinions/advice.
I took him to the groomer at his vet's. I had watched her interact with several animals during our visits and the animals all seemed to approve, so I gave her a chance. She didn't do what I asked her at ALL. I didn't want his face cut at all or his body. I wanted his ears clean shaven and plucked on the inside, and the backs shaved close about 2/3 down. Trim close around his anus, chest short but not shaved, and his belly shaved from the bottom of his breastbone down because he still pees on his belly when he squats.
First, she shaved the top of his muzzle! I wanted a full mustache and topknot.

She cleaned out his ears, but on the back, she just tipped about 1/8".

They look ridiculous to me. She didn't trim his chest hair at all and left a lot of hair around his butt. The only thing she did the way I asked was shaving his lower belly. It's a good thing DH picked him up, because I would have made a scene right there when she charged $60 for this.

Oh, and when she called to let me know he was ready, she got really snarky with me and told me I needed to do a better job brushing him because he had some matts
starting behind his front legs.
This was 2 weeks ago. Last week I had all 4 of my wisdom teeth removed, so wasn't really in any shape to keep up with the brushing and bathing routine. Monday night I sat down with him and worked for over an hour on him. He was better, but his chest is a hopeless, snarly mess. I don't want to cut it all off with scissors, so I remembered a thread about
dematting combs .
I'm crazy scared to try using this thing on a squirmer. They also have
this one which is much smaller and seems like it would work better on the chest. Or should I just buy both? His hair is so woolly on his back, it seems like the bigger one would do a good job without taking off too much, and the smaller seems safer.