L Style Gantry on a 6040 sized machine?

[Sterob]

The best profile to use is 45 x 90 because it makes things easier with mounting ball-screws. However, 40 x 80 will work on smaller machine but you'll just need to make plates to mount BK/BF bearings on for ball-screws.

That appears to be one short cut I won't be able to use as the supplier to have tenatively chosen does not supply 45 sized extrusion., only 40 and even that has to come from the other side of the country.....
Some googling has found 1 or 2 suppliers that use 45 but the quality is unknown.
I'll either have made adapter plates for each bearing block or mount the bearing in another way.