What hardwoods do you have access to? It sounds like the beechwood you are using is not seasoned very well, this is a big deal with wood fired smokers. Look around and see what’s out there in your area. Look for BBQ supply shops or even some sporting goods stores have splits. You really do need good quality seasoned wood.
I actually did a biscuit test as well to test WITH and WITHOUT baffle plates, and the results shocked me
With the baffle plates the biscuits to the right burned almost instantly, while the others didn't even start 'baking'. I guess this partly comes from the radiation of heat of the metal? I'm not sure, but ever since I took out the baffle plates everything is going perfectly, and my cooks are perfect from left to right... Did a chicken yesterday on the right side of my smoker, which would normally have been burned badly... I tried it again just to see if it works and boom... Look at the results...
I had the same problem with my "250 Gal Oil drum Smoker" (search for this upload). Mr. Dave mentioned, to lay firebrick on the bottom of the FB. This worked Very well. But, I wasn't getting enough air to the back of the box. So I made a grate out of angle iron, and placed it directly on the firebrick. This was MONEY! The temp is more controllable and the fire burns constant from the front to the back of the FB. Mr Dave, nailed it.