one more question. i didn't use tape, as it seemed pretty firm inserting the scionwood into the bark. will the bark and wax keep it tight enough where i don't need tape?

I have the feeling it's not going to work on such a large diameter
because there is not enough umpf on old bark to get things pushing.
You'll get some water sprouts growing this year, these are good for grafting next year. The scion will shrink and get loose without tightening to the trunk, you can put some plastic bag over and tape it down around the trunk with a roll or two of electrical tape.

The largest I have done is about 6", and I use nails through the bark flap and the scion to hold it in place. The scions were about one half inch in diameter.

Benny