Ready to Starter Up ! Chimney Cleaning

Ok, time to start the stove up. Cleaned chimney yesterday. Got to much creosote as usual and more down below in the indoor 15 ft of single pipe than above in the 12 ft of double stainless and yes I have sealed all the air leaks in the lower single pipe. Not running hot enough fires and will have to make sure have a good hot fire once a day. I clean chimney 2 times a year and monthly inspect.
This is my 3rd year and now have 2 year old wood supply and will keep ahead of game from here on out.
I have some questions.

1. I have a metal brush that I use and on the site I just saw for the first time something about using a poly brush. Should I be using a poly brush. I clean from inside up. I split the pipe at the ceiling and clean up and then down. My roof is a 2 story with a 8/12 pitch and I am not going up there especially in the winter

2. I installed a slip connector at top of indoor single pipe. I have 2 elbows at top of indoor single pipe that where at about 120 degrees and now are maybe 140. I have opened up each elbow much more to get better draft. You would think with a 27 ft chimney I would have a super draft but I do not probably due to the 2 elbows.

3. I went to TSC and they said I should be using a chemical that you sprinkle on the fire I guess. Does this work or help.

Oh Sorry. So I should be using a poly then. TSC did say the chemical did not replace the brush cleaning it only helped.

Mostly creosote and about 2 coffee cans full. I have seen on this site about 1 coffee can full is OK and anything more is not. I do not run my stove hot enough this is a big problem. I only throw on a couple of splits at a time and not enough bigger hotter fires. This I will change. I asked on a thread last year due to the more creosote being lower and was told to seal up all air leaks on single wall below and this has helped but I was also told maybe I needed to run black double wall below due to the 15 ft length.

I will run hotter fires and I guess use the chemical added to the fire to help loosen the creosote.