Hultafors Mini/Micro Metric Rafter Square MMRS Hardcore Hammers you should go with a

you should go with a MD belt which will leave about 3” of open space

the steps represent 1/8"

it snaps back to exactly 0° with a strict +/- 0

There are several features and marking gauges on the face of the tool

Target Trade: Timber Framers

Hultafors Mini/Micro Metric Rafter Square MMRS Hardcore Hammers you should go with aThe Rafter Square is a robust and versatile tool for all craftsmen. It features a solid aluminum body with CNC machined edges for greater accuracy and durability. The tool allows you to make fast and precise 45 and 90 markings. In addition, its thick edge is useful as a saw guide it can be used directly with the saw against the square for cross cuts or angled cuts. This highly versatile tool can be used indirectly as well, using the scribing notches