NOTES:
I'm recording this here for posterity, and to remind myself as well, since I always forget this method for some reason.
Support beam recipe:
The starter materials for a support beam:
Finishing materials:
Knowing this, you can plan not only the materials you need (multiples of), but the method by which you make the support beams (carrying multiples of that match the support beams you can carry in inventory), to maximize efficiency.
TIP: I use a similar method for making taxidermy kits. I use an expanded bulk storage container (note, not the containers within, the unit itself) which gives it a 100 slot inventory. I use this inventory to store my unfinished taxidermy kits while building them.