Foam backing pad and hook and loop to use for custom hand sanding blocks?

[CoastRedwood]

I would like to 3d print some hand sanding blocks similar to the Festool ones but with custom guides and/or profiles. I can handle the modeling/3d printer side but I'd like some input on creating the interface for the sandpaper.

Any recommendations for a foam backing pad I can buy that's similar to the firmness of the Festool blocks? It's not clear to me how to figure out what firmness I need to get a similar result.

And any recommendations on a hook material to glue on for attaching the sandpaper? This one seems like it's easier to figure out on my own, but if somebody has done it successfully before I'd appreciate recommendations.

 

[woodferret]

Not directly answering the request, but the LS130 kit SSH-STF-LS130 could be what your end-goal is so it's worthwhile to mention it.