I finished the job in two days. Here's a few tips from what I learned.
If you use a handheld grinder with a cutting wheel, have a few extra cutting discs on hand. One abrasive disc is good for 15 - 20 cuts.
When you order your wrought iron parts, get a couple spare shoes, they might come in handy and are cheap.
To cut through the old balusters, you can use a tree branch loper with long handles. It reduces the sawdust and cuts through with one stroke.
If you have a helper, one person can apply the epoxy and place the new baluster while the other can wipe off all fingerprints and smudges with a simple green type solution and do the final alignment. Once the epoxy dries on the baluster it's hard to remove and causes shiny spots
Take your time and let the epoxy set up. If there are any loose balusters afterwards, you can use some epoxy putty (JB Weld) to force into the hole and it will solidify them. I had about three out of 84, so not too many.
The easiest epoxy to use for me was the loctite brand that came in two 4 oz squeeze bottles in a pack for $15 at HD. Just be sure when you replace the caps on the proper bottles - one for the activator and one for the resin. One is red, one is white. Otherwise you will glue the cap on. This one kit will glue about 70 spindles top and bottom.
When the epoxy is setting, try not to be cutting and removing adjacent spindles as this activity will prevent the epoxy from setting properly. Plan ahead so that after gluing in a bunch, you take a break. Try to do a whole section at a time.
The top of my old balusters were pinned with a nail gun. Removing these top halves (bottom halves popped right out) was the hardest part of this job. You need to pull each slowly and rock back and forth. If you get too aggressive you can damage the handrail. Take your time and they will come out. The plus side is that you will find out if you have a weak rotator cuff that evening. Here's the before and after.
Oh - before you point it out to me - I did see that the one decorative S in the final photo is facing the wrong way and I corrected it. It is easy to make a mistake, so be careful.