I am a novice at gourds, but I can tell you that last year "someone" made an accidental large gash in one gourd with a weedeater. The gash went into the flesh, but not through it. I thought I'd take a shot at sealing it-- all I had handy was blue spray paint, which I used on that area. Believe it or not, the gourd grew, dried nicely, I cut out the gashed area and made a birdfeeder.
Now--- dealing with what is chewing on the bottoms is a whole other matter; I'm no help there!

Put some pieces of cardboard under your gourds. There's a number of critters that will eat the skin off. A spray of Sevin may help. I had an apple gourd early in the season that grew in the middle of a wire fence. By the time I noticed it, the wire was already imbedded in the gourd and brown juice was running out of it. I cut the wire and freed the gourd but was sure it was going to rot. A month or so later the gourd is growing fine and the wound has sealed. I've had 3 or 4 with almost all the green skin chewed off and they are still doing fine. As long as the chewing is restricted to the skin and not into the meat of the gourd they shoud do OK. When they are dried and cured the outside may be a little rough but they will still be usable. I wouldn't paint or coat them with anything except maybe an insecticide. I have a picture of the apple gourd that grew into the fence if you want to take a look. It's on my PictureTrail site. picturetrail.com/genepa Gene

I've sprayed Kaolin mixed with water and it stopped all bugs from eating my gourds last year. Gardens Alive sells it under the name Surround. It's basically a powdered clay and bugs don't like the feel of it.