Plum Tree Graft

This year I had some success grafting Plum Trees.
This art is still very new to me, only the second year I've attempted grafting. Last year was a complete failure. This year, I was happy to see two grafts taking.

After seeking information about when to take the tape off, (i.e., watching YouTube videos), the norm seems to be about one month after leaves sprout on the scion. So that is what I did.

Unfortunately, the electricians tape that I used took a lot of the bark off the branch too (see attached photo.) Each unroll of the tape took another patch of bark off.

I am now afraid I may have girdled the very branches I wanted to be most successful.

Hoping for the best, but thinking ahead for future years.

What did I do wrong? Did I wait too long to take off the tape (i.e., did the tree have too much time to grow tight against the tape?)
Is there a better tape to use than electricians tape? Plain old non-sticky wrap doesn't make a very tight seal.

Any advice for the future?

Very interested in this David.  I'm hoping to try grafting some cherries, and maybe plums but have only tried apple family so far with 50% success (I think I managed to get a nice fruiting haw onto Crataegus monogyna this year, although too early to crow yet)
What time of year is best for cherry and plum?
Obviously you can get special grafting tape (see agroforestry research trust tape, which does not need removing and will biodegrade. I steal some of my hubbies special self amalgamating tape.  I'm not sure if it is primarily for plumbing or electrical work, but he jealously watches how much I take because it is quite expensive.  It does need removing, which can be a bit tricky once the branch starts to swell, but only sticks to itself.

Some of the techniques that are out there also include drilling a hole into the side of the branch to disrupt the cambium and insert a graft into it.  They use mastic to seal it.  This can also act as a skin to allow the bark to heal.  New thinking according to something that I read yesterday is to let the tree do the healing naturally.  Here is an example of using a drill: https://www.youtube.com/watch?v=zUvRuxzBIcI
Grafting tape is biodegradable polyethylene and made to allow for the transportation of oxygen and carbon dioxide.  If you are using electrical tape, put the first layer on, sticky side up.  Plumbers tape is too narrow and you may cut into the tree if it rolls.  As for the cost of grafting tape, if you compare the cost of a new tree to the cost of the tape,  you may get 10 grafts from a roll say $1.90 AU each compared to $19 - $59 AU each for the complete tree.

If you have access to non-bees wax, make up some 1" strips of cotton cloth and coat with non-bee wax like making bowl wraps. Just remember the bee biosecurity  and do not use bees wax as it can attract bee pests such as wax moth.  In most countries, leaving bees way lying around outside is frowned upon  Hope this helps with the discussion and success.

I have had really good results using Parafilm. It goes on very easy, stays in place, and has never torn any bark off when I've removed it. I usually don't even remove it myself. It's thin and stretches with the growth of the tree, and will eventually break and fall off on its own as the graft heals and grows bigger.

Oh and it's crazy affordable. I think I paid about $25 for a box, and I've done tons of grafts over the last two years, and I still have a lot left.