Another option would be to appeal to our session with the hope the will accommodate us "weaker brothers" according to conscience? If unsuccessful one could to the Presbytery and then I guess the General Assembly if the Presbytery refuses to do what ought to be done.
Councils err, and Presbyterianism has processes for redress, so why not exhaust all means, and may God bless it! But I would not appeal on the basis of being a "weaker brother." If one holds to psalmody he should do it on the basis that it is a New Testament ordinance, and the ordinances ipso facto bind the consciences of all believers. To claim to be a weaker brother is to maintain it is a matter of indifference which requires accommodation; and as it is already treated as a matter of indifference, the appeal accomplishes nothing.