At this moment I am experimenting with the strings that I am going to use on this Washburn Resonator.
The guitar is now wired with a Martin MSP4250 Bluegrass SP Phosphor Bronze 92/8 hexagonal core, in the Gauges: .013, .017, .026, .035, .045 and .056.
For now that works the best for me, since I really like the warm tone of them.
Another set I have used was the Gibson J-200 Deluxe Phosphor Bronze String .013 set, in the gauge: .013, .017, .026, .035, .045 and .056.
Both sets work really fine, and really bring out a warm tone of the guitar.
Only for now I like the Martin set better when I use a capo on the neck, for some reason it feels better.
The capo I use is the Dunlop Trigger Capo, on the second fret to make the guitar is a E tuning. (since the guitar is tuning in open D).