English muffins using sourdough discard and ripe sourdough

The first sourdough English muffins I tried turned out perfectly, except they were a little floury on the outside. The next recipe I tried didn't turn out so well. They were a cross between a hard roll and a biscuit. I rolled the dough out to 1/2", but these things were too tall when they rose. Then they got taller in the oven. I flattened some of them to see how they would do. I weighed all ingredients, but I don't know if I did something wrong or if it was just a bad recipe. 

Good for tartar control. Very crisp on the outside. ?

Next, I used sourdough discard to make a sourdough cinnamon crumb cake. The recipe kept using the word "batter", but it really was a stiff dough. I baked the allotted time, but it was doughy. I kept checking it until after 1 hr and 15 minutes of baking, I gave up. You can see how doughy it was. In to the trash, it went!

The two recipes were from the same website. I think maybe it had to do with the sourdough starter and the amount I used. The recipes both called for sourdough discard. The muffins used 1 Tb of yeast and 1 cup of starter. The cake used no yeast, but had baking powder, baking soda, and 3/4 cup of starter.

So....I didn't know whether to use a dry measuring cup  OR    a liquid measuring cup for the yeast. I used the liquid measuring cup since the starter was a liquid starter. (King Arthur starter.)

Is this what went wrong?

Next, I made 2 sourdough ciabatta bread rounds. I used a preheated Dutch Oven with the lid. Oven temp 500° F to preheat, then down to 475°F to bake 20 minutes. Then remove lid and bake for 30 more minutes at 450°F. My temp probe showed the bread had reached 205°F before I removed the lid. On the 2nd loaf, I reduced the 1st temp to 450°F for 20 minutes then removed the lid and baked at 400°F for the rest 9f the time.

Again , the loaf was 205°F in the first 20 minutes of baking before I removed the lid. Within 5 minutes, the temp was 210°F. The recipe called for 208°F.

Both burned on the bottom. The 1st loaf was on the 2nd rack from the bottom, and the 2nd loaf was on the 3rd rack from the bottom. The 1st loaf was more burned than the 2nd. Usually, the top gets burned when I make cakes so I normally use the last or 2nd to last rack. I was afraid the 2nd loaf would burn on top, but it didn't. 

It still looks doughy to me.

It wasn't all bad though. I made a sourdough 100% white whole wheat bread that turned out well. Not a lot of rise, but I think wheat breads don't rise much anyway. It had 1 tsp of yeast and 227 g of starter. (Not discard.) 

Is there a trick to getting a rise from wheat bread. It rose 1 "  above the loaf pan, but it ended up about 3-4" tall. It is moist and tastes great...it's just a short, stubby little thing.

Possible problems....

1. Oven was just too hot. Does 475°F seem like a normal temp for sourdough ciabatta?

2. Parchment paper...maybe it caused the bread to burn. I have 3 brands of parchment paper, and all 3 said 410°F at the most. The oven was hotter than that. 

3. What should I go by, the temp or the time? Both should work. 

Any thoughts?

Thnks