time between adding new wood?

Well I don't have a reverse flow but I do have 125 gallon offset stick burner. I start a pretty big fire initially and let it burn with the top of the firebox open for about 30 minutes until all the splits are going good. Then I close the top door and let it heat things up. Sometimes I read about 350 cooker temp or more. I continue to let it burn until I have a good bed of coals and temp gets down to about 275. Then I can start to add meat. This whole process may take a hour or slightly more.

I have splits of all sizes available and choose a size to add by how much temp or flame I want at the time. Once I'm into the cook I go a good 30 minutes or more without adding a split. By the end of the cook the temp is cruising along at a solid 250 with a coal bed about the size of a softball. Often times I have to add a split when I really don't want to because the coal bed is getting small not because I'm losing temp.

Sounds to me that maybe you aren't taking enough time in the begining to get things really heated up. You want to start cooking when you are on the downside of your first coal bed and then add splits to keep your temp.

My exhaust is always wide open with the firebox vents about half when things are cooking.

Hope this made some sense

This is how my fire looks about the time I'm ready to start cooking. Things have burned down considerably since the initial fire. Smoker temp is probably about 275 right now. I do a lot more poking the fire and moving coals around then I do adding splits.

You said you had some recent work done on your smoker. Anything to affect the air flow?
On the average my offset will average about 30 minutes between splits.
Did you try burning bigger splits?
Does your wood have hardly any moisture in it? "Super dry"
Do you have vents you could cut back on your airflow?
I would say you might just have to experiment some.
Hopefully we can help you figure it out.

I have a 180 gallon setup similar to yours and have to stoke it up every 20 minutes or so. Sometimes I have to add more than other times. When the coal bed gets too small I add charcoal...typically 2-3 times during a 10 hour smoke.