If you are using small caliber rootstock with matching sized scions I'd recommend a whip and tongue graft over a cleft graft. It's pretty much the industry standard in that situation. That being said your cleft graft can work and I'd see no reason to put wax on it if there is indeed no air or exposed cambium or wood. Much better options that masking tape as well. It will peel off the soft bark on smaller trees. If you don't have parafilm or grafting tape use strips of bread bags and rubber bands.

If you are doing a cleft graft there will be exposed wood. Pear and apple are pretty resilient, and if the rootstock is actively growing and the weather is warm, it might take without external sealing.

But sealing is very easy and will improve your success rate, why wouldn't you.

if you don't have grafter's wax you could use toilet seal wax, parafilm, dilute Elmer's glue or a number of other things.

If you are going to do a decent amount of grafting you might as well buy some parafilm. I think wax is unnecessary. I've never used wax or any type of sealant and rarely have a failure with apples, pears, peaches....Wrap it with parafilm and you're done. You should get pretty much 100% success with whip and tongue as long as the cambium matches up reasonably well. Apples are probably one of the easiest trees to graft.

Parafilm serves the purpose of wax.

The correct stuff that you would want to use is a flexible vinyl 1/4" tape that can be found at most garden centers. It is green colored- often sold as tie-up tape for various uses in the garden. It is the same stuff that I order from horticultural supply places as grafting tape. It is cheap (probably about 3 bucks for many yards of it) and easy to work with. You can adjust your tension with this stuff and it creates a water tight seal. All the waxes and other assorted things are just a pain to mess with. Once you get good with using this tape, you will understand why it is the most often used. I can sit and watch TV and about 1 union per minute. Cleft grafting is the easiest for a person just learning. It will produce a strong, durable graft on Pear.

One thing I will mention, even I, who has done a bajillion grafts (I used to do contract work for orchardist when I lived in the North), find it hard to do a good job with a regular pocket knife. I use a grafting knife, looks and acts just like a regular pocket knife except that the is an edge only on one side of the blade.

One thing I might suggest is to go out and cut a number of 1/4 branches from your Pear tree. Cut into correct lengths(5-6 inches are easy to work with), pretending one is your rootstock and one your scion. Now, make a bunch of "grafts". You will be better able to understand the "feel" of the pulling of your knife and the pushing of the scion into the rootstock. Use your vinyl tape to make a "mummy". Leave a couple inches of tape loose about an inch under your graft then press your thumb firmly with the tape between your thumb and rootstock. Now, slightly stretching the tape as you work, start winding up, overlapping the tape as you go. When you reach the cut edges of your rootstock, add a bit more tension forcing the tape to mold to the edge, pulling inward. Keep winding up about an inch above the graft and then simply change directions, winding down, always keeping the tension on the tape. Cover any parts you missed on the first pass up. Now, as you get back to where you started, tie the end you have been working with to the "tail" you had left hanging when you started. Just knot it. You are now done. Do this a number of times using your practice branches and all this will make total sense.

One last important thing, get a wash rag use it to grasp your rootstock, letting part of it hang over your finger and thumb that is grasping your rootstock. It will protect you from a severe cut that you will most likely get the first time you go to make your slice down your rootstock. I used to teach grafting classes at a community college; it never failed, someone would say "I don't need THAT". Needless to say I always brought a good amount of cotton gauze and bandages, lol. I can still see the scar on my thumb from that first time.

Good luck, you will do well. Pear was the first species I ever did too. I also did 5... I was never so proud as when I realized all 5 took. I felt like a real hero, lol.

almost forgot to mention, cut your vinyl tape in pieces about a foot long..maybe a bit longer before you begin winding. I made it sound as though you were working with the tape still on the roll. Once you have done it a few times, you will find the best length your particular style of winding will require.