Is there any relevance to total t (testosterone) or is it only free or bioavailable t that matters?

See answer. It is the bioavailable t (free t plus weakly bound-to-albumin t) that is the active forms of testosterone in our bodies which provide t's clinical actions. If there is no reason to suspect a meaningful change in shbg, then total t is a reliable value to follow because it is easier for labs to measure and much cheaper for pts. If total is borderline, then measuring free t or bat is recommended.