Ok we think we got this straightened out. I will edit the original post to reflect this.
The proposed change to the builds instructions is:
Note: The table cuts and build remain the same for all of the following X-gantry lengths.
TUBE LENGTH for X-gantry – FOR TABLES WITH METAL STRUT SIDES:
Note: Testing has not been performed for use with Optional Urethane Wheels.
If you already have an X-gantry size other than listed, cut your strut plates to your choice of size as listed below. You would then need to buy new EMT/tubing and cut to match your choice.
All of the sizes listed will work with the LR3: adjustable table extenders
A. 1425mm (56.102362″) X-gantry length, based on using LR3: non-adjustable table extenders (wood or printed)
B. 1435mm (56.49606″) X-gantry length, based on using LR3: HIDE/PROTECT non-rail side Y AXIS BELTS inside metal strut. This option brings the non-rail side Y Bearing Wheel Bracket closer to the edge of the metal strut to aid in the installation of the mod.
C. 1400mm (55.11811″) X-gantry length, based on using LR3: table extenders (wood, printed, or adjustable).
This option works by not installing the two MDF 1/2" wide spacers along the metal strut as per plans. This allows builders who are building this table and already have a full standard LR3 full sheet build to quickly move to the new table. To use the full area of the design, installing option A or B and the two 1/2" spacers can be done at a later time.