How can I make this search requirement work?

I have a bit of an odd requirement in so far as analyzer is concerned.
Wondering if anyone has any tips/suggestions.
I have an item I am indexing (grade) that has a property (name) whose value
can be "0# (99.995%)".
I am doing a prefix search on _all.
I want users to be able to search using 99 or 99.9 or 99.995 or 99.995%.
I also want the user to be able to copy-paste "0# (99.995%)" and it should
work.

I am currently using the whitespace analyzer - which works for many of my
cases except the tricky one above.
99.995 doesnt work.
But "(99.995" does. Because obviously after whitespace tokenization, the
token begins with (.
I could filter out the "(" and ")" characters. But then "0# (99.995%)" wont
work.
Does anyone have some different suggestions?