34" seems usually short for someone your height. I almost always fit people who over 6' 2" into 35-36" length putters. Very easy to add extension, just make sure it fits snugly. Weights would be up to you, generally you would want to remove about 10 grams of weight from the head when extending putter by 1".

It's an open ended question. It all depends on what feels right for the individual.

Putter length is not directly proportional to height. Your stance and distance from wrist to floor are better markers. Most golf shops will have png fitting putter with an adjustable length shaft. Check to see if you are more comfortable with a different length shaft.

Most repair shops can replace a putter shaft. Even upgrade it to one of the stiff graphite shafts. If your putter is a tool, you can get it upgrade it locally. If you want to keep it authentic for resale or as a collectible, send it to the Studio. Once modified, the Studio won’t refurbish it after that.

I am 6'2" and all three of my gamers are 35". They differ in weight, but all are Anser style. Two Scotties and one png. Depends on the greens I will be playing on and time of year. One Scotty is 30gm and the other is 35gm. A putter is a personal thing and you just have to play around and practice, paractice, paractice til you get that feel.