LA 360 - 0.030" Undersize Main Bearing Clearance Questions

Just to plan ahead, I started looking around for 0.001 undersize bearings this morning. Options are extremely limited for main bearings. I basically only found 3 options, all of which are sold out pretty much everywhere:
There are also 0.001 in. undersize bearings for 0.010 in. main journals. Same availability issues though:
This makes me wonder what racers are doing these days to get the desired clearances. I guess you either need your own personal stock pile of main bearings or more cranks are getting ground to a target clearance.

It's also kind of interesting that the same availability issues don't seem to exist for rod bearings. Summit has plenty of options for rod bearings that give 0.001" of extra clearance. Heck, even Summit themselves makes a rod bearing for SB Mopar:

Summit Racing Race Series Rod Bearing Set - SUM-481HXS

I wonder what the thought process is there. You'd think if there is enough demand to offer rod bearings that the same demand would exist for main bearings. I guess maybe it comes down to the 360 having a different main journal diameter than the 273/318/340.