Macro for aligning on plus/minus?

[Sinvicta]

I know you can align text on a decimal, but I need to align columns in a
table on a plus/minus symbol (I actually use an underlined plus because I
have found that the sysmbol doesn't always transfer to a different computer).
I have columns of text in which each cell looks something like this: 42.5 +
12.4 (with the plus underlined). I can't use a monospaced font, so even
aligning on the first decimal or just centering the text will throw off the
alignment of the plus/minus (eg, 11.1 + 81.1 versus 88.8 + 88.1 does not line
up on the plus/minus). Is it possible to get around this or to create a macro
to do this?

 

[Sinvicta]

I forgot to mention that I usually have supercript letters attached to the
end of the numbers which really throws off the alignment. For example: 42.3
+ 12.4ab, where the ab are superscript.

 

[Jezebel]

Set a right-tab closely followed by a centre tab and a let tab. Then use
tabs instead of spaces.