Think of a linen string as piece of wire. You bend it enough it'll break. The more you twist it, serve it tight, the harder it becomes and the quicker it'll break. You can get more wear out of a linen string if you filp the string and start bending in a different spot.
I think that the quality of linen string today is less than years past. You can still make usable strings but it's life is pretty limited. Here's a couple things that I hope will help you out.
Use on longer bows (string angle where you nock the arrow will be less).
Make the string up in the direction of it's twist (for flimish twist), usually clock-wise.
Flip the string after about 100 shots.
Use no serving or light twist serving.
Eight strands is about all I could use for proper nock fit.
If you do self-nocks then you can use a higher strand count because you can easly fit the arrow nock.
When it's all said and done, with the quality lined available today, it's probably not worth the trouble........Art