Here, I will summarize what I think about metal strings and metal wound based on literature and information on web sites and catalog of string manufacturers. I will update as I get new information.
String slide rule
Pyramid and Kuerschner distribute slide rules that aid to select appropriate strings (nylon, fluorocarbon, gut, or metal wound) based on scale length, pitch (Hz), and tension. They are great things to have, but often scarce.
Lbs (or lbs,lb,lB,LB)
Lb: (paund) [n] <<[[pl] lbs. (paundz)>> (abbreviation of pound)
The word "pound" is a British monetary unit (1pound = 100pence) and also an Imperial unit of weight. Pound customarily used in US is the latter and about 500g (453.6g to be exact).
To convert lbs to kg or vise versa, use lbs / 2.2 = kg or kg x 2.2 = lbs.
The word "thou" used as an unit of thickness in English means thousandths of an inch. 1" is 25.4mm, therefore you can convert thou to mm by multiplying it with 25.4 and dividing by 1000. If you find a note on 1st string like "e' : 22.5 thou", for example, you would know the thickness is 0.5715mm, because 22.5 x 25.4 = 571.5.
On treble strings which are not metal wound, one can choose nylon, fluorocarbon, or gut strings depending on one's preference. It's convenient to know how to find equivalent strings of different material. It can be calculated from their specific weights, but I will list multiplication factors below. You can find close enough strings without using string a slide rule.
r' = r x 1.12 (bass, metal wound strings)
[bass side] C1
D1 E1 F1
G1 A1 B1 C D E F G A B c d e f g a b c1 d1 e1 f1 g1 a1 b1 c2 d2 e2
f2 g2 a2
b2 c3 d3 e3 f3 g3 a3 b3 c4 d4
e4 f4 g4
c5 d5 e5 f5 g5 a5 b5
Tone range of typical guitar is the following, using the tone names listed above. The suffixes like 1 and 2 sometimes are substituted by ' and ".
1st string (e1)
2nd string (b)
3rd string (g)
4th string (d)
5th string (A)
6th string (E)
Clever idea on using tuners.
Many electric tuners distributed inexpensively today are for guitars, but one can use them for ukulele and other stringed instruments. Using them for lute and mandolin or in noisy place, it's better to use a clip on pick-up (also called as a contact microphone), though the tone range of lute and mandolin is not quite the same as that of guitar. I've purchased one about 1000 yen (about $10).
Strings on 19th century guitars,
ProArte light tension in a pinch. Seaguar is always a good choice.
Try whatever seems usable.?
As I noted at the beginning of this corner, there is a complicated relations between the instruments and string used on them. It's not a bad idea just to try whatever seems suitable for a string. You'd better to know length, thickness, and weight beforehand. Aren't gut for badminton or tennis rackets or strings for shamisen usable? Well, I should practice more before fooling around finding alternatives.
What your neighbors are using?
Watching others' instruments carefully, professional or expert players tend to prefer higher tension both steel and nylon strings. They probably like strong sound higher tension offers. On the other hand, beginners and those lack grip strength prefer lower tension settings.
Worth a try
Those who master fishing lines will conquer stringed instruments (really?).
That's folks. I'm tired, now.