There is absolutely no merit to being machmir out of doubt. We are supposed to learn the halachah in consultation with a rav. Being machmir out of doubt is a confession of ignorance or even laziness, neither of which are positive traits! With a rav we can determine when to accept the stringent opinions and when to follow the lenient opinions depending on our own character traits and susceptibility to the yetzer hara in that particular area. And we must never insist that others follow our own chumrot; that is the height of arrogance.
Regarding following a rav who paskens a minority opinion, if you have a rav you should always follow him in his leniencies and his stringencies. And if you don’t have a rav you have not fulfilled the positive commandment in Avot. None of us are strong enough to pasken for ourselves in difficult issues. Any good rav will tell you who are the poskim HE relies upon and they will be people whose names you will recognize. In comparison, the talmud has terrible things to say about people who shop around for opinions they like — it is a way to enable the yetzer hara, big time.