slight hijack but…. in a similar situation but with a woeful Sora setup (look suspiciously like Tektros). So would upgrading calipers be better than changing the sti’s? Kinda stuck anyway as they’re 9-speed, but I can barely reach the bloody things when I’m on the drops!
To you and OP, there are different leverage ratios for Shimano brakes out there. I think the latest Tiagra upwards has a different lever/caliper pull ratio, so have a look at the compatibility charts before buying new calipers (they could be quite spongey otherwise.)
If you can’t reach them on the drops, consider a different lever/bar position or different bars (I’m not sure which brakes have reach adjustemnt, that may also help of course).
Edit – I would say even basic Shimano calipers would be worth considering in addition to some good pads, compared to Tektros. And Campag calipers will have the basic issue that you won’t have a QR on the brake to get the tyre past (it’s on the lever on Campag, caliper on Shimano).