It's about getting enough air to the fire.
One thing I noticed after I added high pressure AOF and AUF was that I no longer needed to criss cross the firewood. Apparently the abundance of high pressure air negated the need to criss cross the wood. If you search out the topic you will find it on the Proctor site, combustion efficiency.
You however need to learn the difference between a squirrel cage blower and a high pressure blower. Just because a squirrel cage blower moves lots of air, it is not high pressure air. The difference is huge. I like to describe it as a squirrel cage blower flings the air, while a high pressure blower throws it, The high pressure blower had paddles that each throw the air at the blower outlet. It's not the volumn of the air but the pressure of it. While I lucked out getting a HP blower free, most need to pay big bucks for one. My free one came from a closed down factory, it was mounted up high in the rafters and a friend discovered it was still there several months after the factory had been closed down and cleaned out. It was actually used to create vacuum for presses punching doilies out of paper. It was 3 phase and had to get a new motor, and mount, but in the end it worked perfectly as a high pressure blower and one I could afford. If I recall it cost me 1 qt of syrup, maybe it was 2.
Anyways, back on topic, this could solve your efficiency issue and more than doble your gph. While my efficiency was quite good before, with the HP blower AOF/AUF it rose about 20% more after while burning about 1/4 less wood, a win win in my book. Take note that I ran HP air to both under the fire and over the fire, not just over it like the report about combustion efficiency describes. I suspect my gain would not have been as good and likely I would have needed to criss ross the wood too. For me to get the HP air to both, the blower was coupled to a 4" pvc pipe, outside, under my head tank. From there it went inside the sugarhouse using 3 long sweep ells to end up on the floor facing the arch. I had a trench for it. As that 4" pvc pipe got under the arch, I split it using a 4x3x3 wye. One 3" went in under the back of the arch in a 4" heavy gauge galv. steel pipe, the pipe was on the floor and was ended and capped at 6" short of the front of the arch. In the pipe I had 3 rows of 5/16 holes, one row top center spaced about every 3", and one on each side facing theouter edge of the grates spaced the same. Each 3" pipe had a ball valve in it to regulate the portion of air to each. The other 3" went up into the slope of the ramp behind the firebox in the arch in a 2x2 square tube, which split into 2, one going to the rt and one to the left side of the fire and each had a 1/4" b;ack pipe nozzle, facing downward about 12-15 degrees and facing the opposite side grate. The nozzles went completely arond the fire except over the doors. I'm going from memory, but I think I had the AUF valve open about 1/3 and the AOF valve open about 3/4. For better details look at my original post from way back when I had first built the system. In the beginning I experimented with various valve settings, but in a very short time I found what worked best and never adjusted them again. My big question in the beginning was if the 2x2 tube I used would be large enough, Since I never tried using larger I'll never know, but the results were fantastic so I never changed them. Where the AUF transitioned from 3" pvc to 4" steel pipe (like smole pipe) I cut slits and pushed it over the 3" pvc and clamped it using a hose clamp and sealed it with duct tape. The 3" to 2x2 square I used a Fernco connector sized to do the job, I woyld guess it was 3.5" x 3 maybe, and hose clamped it together. Bothe connections were under the arch, not in the heat of the fire.
Dave Klish, I recently ordered a 2x6 wood fired evaporator from A&A Sheet Metal which I will be converting to oil fired
Now have solar, 2x6 finish pan, 5 bank 7x7 filter press, large water jacketed bottler, and tankless water heater.
Recently bought another Gingerich RO, this one was a 125, but a second membrane was added thus is a 250, like I had.
After running a 2x3, a 2x6, 3x8 tapping from 79 taps up to 1320 all woodfired, now I'm going to a 2x6 oil fired and a 200-425 taps.