I am 6"-2" and use a 59" cue. As far as length goes, you are on the right track. The 59" (combined length) of that cue will be much more comfortable for you. I am also 'long armed' so I could easily (and have) use a 60" cue. I do not like the feel of a 60" cue however, so I stated making my own.
I have found that even 1/2 inch longer shaft length makes a HUGE difference in the way a cue plays. The entire shaft taper must be re-engineered to deal with the added length. I am spending a great deal of time to get my 29-1/2" shafts to play like 28-1/2" shafts (a classic 57 inch cue). And let me tell you: it is not easy!
With a replacement shaft, I have to assume the joint and tip diameters are the same, so where is the added spine coming from? I deal with this problem... As you add 'spine' (more wood) how do you deal with the weight? (my preferred shaft is around 6 ounces right now) That weight greatly affects the balance point of the assembled cue too... It is a big puzzle for me, and the main reason (that and the fact I have no time to devote to cues at the moment) I have not sold a cue. I need to find that perfect taper that will give me exactly what I want the shaft, and more importantly, the assembled cue, the feel and playability I want it to have.
Sorry for the rant...
I have also seen inserts that extend the cue length by placing a piece between the butt and shaft. Due to the pin, this generally needs to be about 2 inches long minimum, and that would be too much for me personally... I have no idea how a cue with two joints close together would play either. I thought I'd mention that as an option I am aware of.