So I've decided to re-do the mastic around my pool and came here for advice. (can't find a decent contractor to do the work, so I've decided to DIY). The old mastic is very old and hopefully with it being like this for the past few years hasn't done any permanent damage to the surrounding deck and coping.
Here's a shot of what it looks like - can anyone tell me what I should be looking for to see if there has been damaged caused by it not being sealed for so many years?

As i investigated the many products out there to make the seal, I've decided to stick with Deck-o-Seal as a replacement (what was originally installed). The first issue i have is that the color my wife wants to use will be different from what already exists (we are getting a custom color), so the removal of the old mastic is even more crucial, especial since the old mastic was poured poorly. So as I've been cleaning out the gap I've noticed that the deck (grey cement), is about 1/8 inch higher than the Terra-cotta coping around the pool - the height slightly varies at different areas, but certainly higher up to around 1/8inch. (shown below) -- could this have been caused by settling of the cement over the years, or is this typical of pool construction?

With this height difference, I'm concerned that you will be able to see the old mastic color on the edge. In addition, I'm concerned that this small height difference may lead to water collection on the seal. I've been using a scraper and tested using a drill with a wire wheel, but it's leaving marks on the concrete that don't look so good (see below) -- any advice in getting all of the old color off of the cement? Also, if the coping and deck are at 2 different heights, you have to pour to the lower of the two, correct?

Also, regarding the removal of the old Mastic -- any advice on getting it off the Terra-Cotta? I'm currently using #2 Steel Wool along with a metal scraper which seems to be working well enough, but very hard to get it off the mortar between the bricks....I can't use the wire wheel, (will mess it up)

I have more questions, but this post is getting long....basically wanted some advice on the removal and prep...it's taking me a long time just to do one side, but i want to do it correctly and have it last a long time.
Thanks in advance for reading and look forward to some comments/suggestions/tips
Here's a shot of what it looks like - can anyone tell me what I should be looking for to see if there has been damaged caused by it not being sealed for so many years?

As i investigated the many products out there to make the seal, I've decided to stick with Deck-o-Seal as a replacement (what was originally installed). The first issue i have is that the color my wife wants to use will be different from what already exists (we are getting a custom color), so the removal of the old mastic is even more crucial, especial since the old mastic was poured poorly. So as I've been cleaning out the gap I've noticed that the deck (grey cement), is about 1/8 inch higher than the Terra-cotta coping around the pool - the height slightly varies at different areas, but certainly higher up to around 1/8inch. (shown below) -- could this have been caused by settling of the cement over the years, or is this typical of pool construction?

With this height difference, I'm concerned that you will be able to see the old mastic color on the edge. In addition, I'm concerned that this small height difference may lead to water collection on the seal. I've been using a scraper and tested using a drill with a wire wheel, but it's leaving marks on the concrete that don't look so good (see below) -- any advice in getting all of the old color off of the cement? Also, if the coping and deck are at 2 different heights, you have to pour to the lower of the two, correct?

Also, regarding the removal of the old Mastic -- any advice on getting it off the Terra-Cotta? I'm currently using #2 Steel Wool along with a metal scraper which seems to be working well enough, but very hard to get it off the mortar between the bricks....I can't use the wire wheel, (will mess it up)

I have more questions, but this post is getting long....basically wanted some advice on the removal and prep...it's taking me a long time just to do one side, but i want to do it correctly and have it last a long time.
Thanks in advance for reading and look forward to some comments/suggestions/tips