I too have a pair of the last Kestrel 2's.... a truly superb speaker by any measure, and although I now have several other pairs of speakers significantly higher in cost, I've found it difficult to let the Kestrels go as they were the first pair of speakers which really gave me deep 3D insight into reproduced musical magic !!!
Indeed they are very revealing of the slightest changes upstream to them, I too tried numerous makes of cables and at the time I last ran them I used DH Labs Q10 in shotgun configuration, which were most favoured over others, and most obviously an improvement over a single Q10 run with jumpers.
The shotgun run of Q10 added greater 'mass' and density to the presentation without slowing things down, and they are rather low cost in the crazy scheme of cables... excellent value which I can highly recommend with the wonderful Kestrel 2's.
Btw, I used this combo with numerous amps, from solid state Bryston mono blocks to push pull KT-88's, single ended 845's and many more... they never failed to deliver some of the most natural, out of box sound I've heard to date !