You know... I don't think proportions are that important, unless you have something very small compared to your body, like arms or hands...
If you have long legs, you should have at least long arms, otherwise you would looks like a T-Rex.
To be honest, I don't think a few inches off from a good proportion will kill your body, I decided I don't care much for my proportions and will do my original 12cm and be 178cm, being long legged sounds more like a perk than a flaw to me anyway, and you can only have long legs if compared to a torso, so yeah... I prefer long legs and short torso than short legs and short torso xD
Yes, that's why I ask whether proportion or final height is more important to you. If you don't feel proportion is important then do as you wish.
But you are aware that your legs are relatively lengthy for your height. Most guys at 5'5 wear 28-29" inseam but you already have 31" inseam. At 3" increase you will be at 34" inseam. 34" inseam is the longest pants inseam for most clothing manufacture and is typically worn by the tallest male in the general population. With 4" increase, you will be at 35" inseam with the body of 5'5.
So it boils down to whether you prefer final height or proportion. Unfortunately, you won't have both in your case.
Long legs are beautiful but provided that you have tall upper body and broad shoulder. If you have shorter upper body, it will accentuate your short upper body frame. You probably don't know what I'm talking about until you're actually have experience and witness what I have seen. This is actually what stops most of us from being 6'2.
Yeah, doing 7" first is good since you are going for 2 segments. Go for 7" first and then consider whether you like to go for more and by how much. Cheers.