I'm pretty sure either should beat Fudo offhand?
Anyway you should look into Uzuru. Weapon skill trials aren't hard and either of the Katana's should be better than Senjuinrikio or Fudo. (43damage and STP+8 is best right?)
Other than that I think... basically every single fully upgraded Magian weapon is better than either of your current 2 katana's? Also there is Hochomasamune
to consider if you'd rather not do trials. Or buy a Kakko
Anyway I'm going to attempt to get Hochomasamune for main hand, and offhand the STP+8 Uzuru, because that's the best time:effort:reward ratio combination I can see available at this time, personally.
Does anybody recall the STP amount to get a certain-hit-to-100 number? I believe that with Rajas and Brutal, Usukane feet put you on an even number of hits to get to 100? So without Usukane feet, the STP+ Uzuru should be pretty nice right? I've sorta siderailed this. Oh well.