A complete list of tank mates and their sizes could help us help you avoid mistakes.
I'd advise you to carefully and diligently browse through Cat-eLog on Planet Catfish and find catfish that would suit your taste and size requirement. You can filter the Cat-eLog by size too but it is limited to like 20 hits, you gotta keep doing it with many entries...
The catfish that are available in the hobby have more photos - the more photos there are in the Cat-eLog entry, the more available a catfish would be generally, this is how you judge. No reason to look at the catfish with museum photos only or with one or two real life photos.
Compile a list and post it here and we can go from there.
Off the top of my head I could name many catfish from 5-10 catfish families but I don't feel like listing 50 catfish right now. I feel you should do it haha...
Many people will suggest concrete catfish and I am thankful to them. Like David suggested bolt catfish... but I for one need to know other tank mates plus that your jardin is not a killer, and its age and size... perhaps it will turn into a killer soon. Jardinies are infamous for it.
So the query field is too wide for me and the jardini makes me uneasy.