Hi Colleen,
The pulse and tongue make me think first of Xue Fu Zhu Yu Tang. It moves Blood from the upper burner, which has the western effect of decreasing afterload and increasing peripheral perfusion. This can be enough, sometimes, to reduce at least hilar edema. It should be enough as well to reduce right-sided changes such as pleural effusion, since these are also responsive to reductions in central venous pressure and increased peripheral circulation.
From a Chinese medical point of view, the dark tongue indicates stasis; the weak pulse coupled with its wiriness is typical for Blood deficiency being the cause of the stasis, and resulting in vasoconstriction that leads to the accumulation of the blood supply centrally. The Blood deficiency also creates the dry tongue.
Your suspicion of a TB obstruction also warrants investigating, and you can use Xiao Chai Hu Tang simultaneously if you wish. It also enhances peripheral perfusion. It does this best, however, when there is an adequate blood supply, and the weak pulse and dryness suggests that isn't the case. The classic pulse calling for Xiao Chai Hu Tang is thus deep and toned and relatively forceful.
I like your idea of Rehmannia Eight, too. That also fits the pulse and tongue. In practice, the way I figure out which to use of two competing formulas is to needle acupuncture points that go along with each of the formulas to see what the pulse responds to best. So if BL 23 had the best effect, Rehmannia 8 is the best call; if GB 34 helped, then XCHT is a good call; or if BL 17 made the biggest difference, then XFZYT is the best option. Is that something you can do to help distinguish which option is the best? In the absence of that data, XFZYT has the most immediate benefit in cardiac disease and the greatest potential for undoing cardiac pathology because of its powerful effect on circulation.
Hope that's helpful advice. Other supplemental therapies - CoQ10, taurine, magnesium, etc. would potentially be helpful here as well. But if that is too much to give, then XFZYT is where I'd start.
Steve