Just saw this thread. There are 4 good customers on the last 4 posts here, but I'd like to ask a bit about this myself.
First, I personally have no experience with a KoAloha Tenor. Nonetheless, I can pretty much guarantee it's not braced lighter than ours. We build Tenors with construction more typical of a Soprano.
The HML-RWs that H50, nong, & ww11 use are relatively high tension when tuned to C on a 17" scale. They're designed for that - a finger-picking, low action set, some would say. The ML-RWs, on the other hand have substantially less tension. Are they less than a plain set? I also don't have experience with some of those plain sets mentioned, but based on the way most people formulate those type of sets I'd say the MLs will have somewhat more tension. Nonetheless, it's very hard for me to think of them as "high tension".
As I mentioned, I have no experience with a KoAloha, but it would seem very strange to me that any Tenor would be under significant strain with an ML-SW set. For that matter, we have no problem with the HMLs on our own super-light construction. It's simply that lightly braced soundboards have no need of high tension to produce responsive sound.
JJFN has actually played MLs on a KoAloha - it would seem to me to be an excellent choice based on some of what I'ver heard here - probably a better one than the HMLs. But has anybody had bellying or other structural problems with a KoAloha? I've seen a KoAloha Soprano, and know the tops are thin, but the unibrace, if I remember correctly, is above the bridge, and very strong. If that memory serves me correctly, it would be hard to cause structural damage to that arrangement.
So I'm thinking more that higher tension is unnecessary, not dangerous. Or in our case, an HML set might be overkill, unless you simply want a low action set-up. Seems to me MLs should be fine for normal action. And if you want to go even lighter, and keep the clear, balanced sound of a double-wound set-up there's also the LML-RWs or even the single wound LL-RWs (a tension to suit every taste and situation).