Underweight and gains

I believe I am a bit underweight, (5’10” 164 pounds). I am familiar with and have done macro tracking, the question is, if I increase macros and continue to track weight and waist measurements how much weight should I gain and how would I know if it is good weight? I would assume a small increase in waist size is unavoidable but a large increase in waist size would indicate I’m not gaining good weight.

I don’t know anything about you other than the above, but you’re about 40-80lbs underweight depending on the context.

Wow. So I guess I’m more than a bit underweight. Looks like I need to start increasing those macros and see where/how the gains happen

Exactly right.