Troubleshooting pocket rocket to burn paint off a barrel

I can’t seem to get a good down draft from my pocket rocket.

The 6” intake stove pipe is an inch from the bottom of the barrel.

The 6” chimney is 2 inches from the bottom of the barrel.

Idea 1: remove the spark arrestor.  No change.

Idea 2: raise the chimney to be a foot from the bottom of the barrel. No change.

Idea 3: add another 2 ft section of stove pipe to the chimney.  This helped a bit but still not a strong draft. Competing chimney effect.  Photo attached at this step.

Idea 4: add another 2ft section of stove pipe to the chimney. This made it worse.

Idea 5: remove one 2ft section of stove pipe and raise the chimney so that there’s a 1.5-2ft gap between the bottom of the chimney pipe and the bottom of the barrel. Helped a bit.

Idea 6: chimney pipe is too leaky from open screw holes. Plug them or use new stove pipe?

Should I try smaller pieces of wood?
Should I have primed the chimney?
Should I have used an 8” intake/exhaust?
My arms are getting tired of manually trying to change the draft.

After 4 hrs, is there now too much ash buildup? Should I shut it down, clean her up, and try again?

I aim to get a good ‘rocket’ sound and no competing chimney.

What does the other end look like? As in, what are your burn tunnel and heat riser made from, and what are the dimensions? You seem to be doing all the right things on the outlet side so let's suss out the input. [EDIT: I missed the bit about "pocket rocket" and of course there's no burn tunnel or heat riser. D'oh!]

This is another thing I've used stale petrol for in the past. Inevitably I end up getting out the wire wheel.

What seemed to work best was raising the gap at the bottom of the intake by 4 inches and pushing air into the feed using a shop vac. I didn’t have to use a shop vac but it helped bring the temps up from 500/600 to 800/1000.

As you can see from the photo, I was only able to get paint off the bottom 2/3s.

Looks good so far!
I'd try spraying oil onto the outside of the barrel,  filling it with wood and burning it with the lid off.
Add forced air as needed.

Try using a wire brush whizzer in a 4” grinder, takes 40 mins to strip a whole barrel clean.

I believe the chimney isn't suppose to extend into the barrel.

The hot air will be pulled up the chimney so it won't heat the top section of the barrel.