The gum should extend fully to the sides of the sealing flap. As it is there are loose pieces of the flap about 1/8" - 1/4" each side which could get ripped or caught. Flap width is about 8-3/4". Gum width needs to be about the same.
I send lots of mail between Michigan and IL. which is important and confidential. When I have just small amounts I use these envelopes and they are perfect. I love the seal as I hate the taste of licking the envelopes especially as many as I send some days.