The Kallium string calculator is down at the moment. That is where I usually go. I would say you need bigger. The stringjoy.com tension calculator only goes up to .135 for biggest string and at 34 scale is 32.9 lbs. That is floppy. Bump up to a 35 scale and you can get to 34.8. I still think that is a little spongy. I like my tension about 36-38.
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My Dingwall Combustion has a 37" scale length on the "B" string with .135 and I have a drop tuner down to Ab0. It is floppy there.
I only dabble in 5ths tuning, I haven't committed. I have a bass with 5ths tuning. A Frankenfender Jazz/Precision fretless. I keep it in 5ths to play with.
I got my strings from Kallium.
I used their tension chart. (when it worked) Shooting for 37 lbs, I ordered a set:
C .124 36.9 lbs
G .082 37.2 lbs
D .055 37.7 lbs
A .035 36.1 lbs
For a close to 40 lb tension, I could have ordered:
C .130 40.4 lbs
G .086 40.7 lbs
D .057 40.4 lbs
A .037 40 lbs