Counting Undersize bearing--> Which direction?

[Geri]

Hello together!

I need your help again with my 1955 chevy inline 6 Motor. I have a logical Problem to understand the counting-system

I measure the Main Bearings and the Rod Bearings with a Plastigage stripe. The clearance is on top of the highest tolerance. I want to replace them with the next selectable undersize.
For example: On the main bearings its a stamp with 002". What is the next undersize to minimize the clearance? 001" or 003"? Sorry for the supid question.With counting the oversize i have no problems. But how is it counted by undersize????
Is more also more or is it getting less??? im confused

Thanks for help

Geri