New brakes for 90s road bike I am riding 90s road bike with Shimano 105 dual-pivot brakes and brake levers, and 2x7 downtube shifters. Since braking becomes less and less reliable I want to replace both brakes and levers with something new.

There's a plenty of good opinions on 105 br-r7000 but I am having hard time to find matching levers. I don't think there are any compatible shiftless levers. Can I go with cheaper claris shift levers or do I need to pay for 105?

Bonus question: could I use 11 speed 105 shifters to work with 7/8 rear derailleur if I do STI conversation?

EDIT:

First, thanks for so many great comments. I see I have missed some important information:


my goal is to improve braking performance - it feels underpowered and my rear brake lever has a crack already.
I have already replaced cables, brakepads (swisstop) and my bike is running brand new wheels (frame was cold-set to 130mm)
fit 28mm tires


From what I have found, here are some interesting brake / lever combinations:


Shimano BL-R400 ($35, brake levers, no shifter, SuperSLR) + BR-R2000 ($50, NEW SuperSLR)
Claris: ST-R2000 ($130, NEW SuperSLR) + BR-R2000 ($50, NEW SuperSLR)
Claris+105: ST-R2000 ($130, NEW SuperSLR) + BR-R7000 ($75, SLR-EV) 
105: ST-R7000 ($185, SLR-EV) + BR-R7000 ($75, SLR-EV)
SRAM S 500 ($75 brake levers) + SRAM Rival 22 brake ($75)
Most likely the problem is not with the actual brakes, but cables and brake pads. Replacing these is very likely to fix your problems.

If you want to replace everything and keep everything in official Shimano spec, it seems that there aren't non-shifter brake levers. The options are to install the expensive and useless shift levers, non-Shimano brakes or use a non Super SLR lever that results in slightly mushier feel.