When my partner initially started riding drop bar bikes, one thing she struggled with was being able to brake properly, her hands were not as strong as an average male's nor were they as large. This lead to her developing back and arm pain whenever she would need to descend and brake as she had to rotate her whole forearm around to be able to even reach the levers, they were simply too far away for her to reach them normally. This was a serious struggle for a single bike, let alone a tandem bike. Our tandem is fitted out with the classic Mafac high-profile cantilever brakes. This style of brake has an inherently low mechanical advantage, this means that it requires a lot of hand pressure to get decent braking force; the flipside is that you get a lot of rim clearance which is why you see a lot of cyclocrossers using them.
The first levers that we used on the tandem were Shimano 600 units from the early 80's. These are a traditional non-aero design which have the exposed cable outer exiting from the top of the brake with a slotted lever. These have a slightly lower mechanical advantage than modern levers, and gave quite poor braking due to this. Braking from the hoods was marginal at best. They were nearly unusable by my partner due to the longer reach of about 83mm
Ergonomically I generally like these levers from the drops, however I find modern and aero levers much more comfortable on the hoods. This reflects how people used to use the drops a lot more than they do now, there was less focus riding on the hoods in the past.
So the next step was to move to aero levers, these type of levers became popular sometime in the 80's and their distinguishing feature was that the cable now exited through the rear of the lever body and was hidden underneath the bar tape. This was part of the 80's aero craze when the market was going crazy for this kind of thing. These types of brake levers typically feature better braking from the hoods as well as a higher mechanical advantage than the older style levers. This model is the Dia Compe GC-07H which has a nice retro looking drilled lever blade which I thought would match the bike. Sadly the fit of these was not much better, braking from the hoods was improved however, the drops position was near borderline for me as the reach was even further out at 95mm, this was understandably worse for my partner.
So after a bit of research I decided to give the Tektro RL320 levers specifically designed for smaller hands. Initally I shied away from the Tektro series levers as they appear to be copies of the Campagnolo lever shape which I think would look too modern on a vintage Jack Taylor tandem. However after installing them the braking from the hoods was better than with the Dia Compes and braking from the drops was slightly less powerful as the shorter lever meant you have slightly less leverage. However overall the hoods position was a lot more comfortable and braking from them was much less tiring, it felt a lot like a modern brake/shifting lever.
For my partner, these were a revelation, she was able to now brake with full force. Previously she could not even reach the levers from the bars! These were at about 75mm reach which is a fair bit shorter than the other levers we tried. For me the transition between the hoods and the handlebars is much flatter and wider which makes it a lot more comfortable.
The search for the right lever was somewhat more difficult than I had initially thought, it made me aware of how anyone with hands significantly smaller than the average male is at a disadvantage. This might not have been apparent to me had I not owned a tandem!