I have the women's baselayer crew 170 and the balaclava, which I sewed together and use as a hoody. I don't think the men's shirts come in anything lighter than the midweight 230. I can vouch that the shirt is very soft and machine washable and dryable and comfortable and certainly a good buy.
However, now that buffwear has a merino buff, I have ordered one to be a "portable" hoody for my older, beatup but still lovable, smartwool l/s shirt and maybe my s/s merino shirt.
My son uses the 230 weight shirt and longjohns for work and likes them. However, he doesn't hike, so the midweight works for him.