Numeric particles

Hello. I am trying to create particles that display a number, 0-9.
Following this A new, community-hosted Unreal Engine Wiki - Announcements - Unreal Engine Forums
tutorial I created a SubUV texture, created a material and particle system and the basics are working.

The SubImage Index module has a Uniform Float Distribution 0-9 and under required - Sub UV, if I have the random option, each new particle displays a random number. So now I wish to control precisely what number a particle has but that has proved problematic. If I select Linear, the particles starts constantly changing their numbers.

Now, the intention is for the SubImage Index module to have a Particle Parameter, So setting that, the particles stops constantly changing their number. But as I set the parameter through blueprint, all the particles change their number to that parameter.

How can I say that only the new particle should have a specific number? Any suggestions?