I cannot help you with the fractions; I only use decimals (although it looks like the values must be over 12 inches before it displays the values in feet-inches).
For your first question, if your dimension names are the same for all 24 parts you can copy and paste the 3 rows between models. Of course a macro could be written to do the work.
I repeat the context:
I intend to have a BOM starting from parts that are created by "Insert new part" . Doing this, I need to catch dimensions (3) in each part individually as described in the picture, because I want to have these 3 dimensions in the Bom. All parts are linked to the assembly master sldasm file, in any case I hope.
The questions was If I have to do this for each part individually ? (the parts are different). Is not about doing 24 times the same part (as in the picture) but for each of them to spend time cliking 3 times at least in graphic area and 3 times in Summary Information table under named custom column (wich is in File proprietes and system info).
So that was my question if it is not other way catching all of these part more automatically, (may be have a new template when insert new part, already associates withs these dimensions values).
How the experts do this?, do they like me, any parts the same way ? (I am not en expert). If they do this, I have got my answer (I'm expert now) and I did not skipped any other important trick without my knowledgement. And I'm like a pro.
SW 2012 release for now
Also, you can look into Custom Property Tab Builder to push those dimensions into your parts. If you open an assembly with all your parts, you can select them all and push the dimension names to those properties:
Above, I only have 1 field, but when you create your Custom Property Tab, you can create your 3 fields how you need.