What's the proper way to mount antenna mast to the side of a house?

Question

I'd like to mount an antenna mast to the gable end of my house. I was planning for the mast to extend from ~10 feet above the roofline down to the ground. I've seen wall mounts specifically for masts, but they seem kind of expensive ($62 for 2?). Also, they seem to be for mounting the mast outside the eave.

I've noticed that electrical weatherheads are installed differently when they're on the gable end: The conduit is mounted to the exterior wall with brackets that don't leave a gap between the conduit and the wall. Then the conduit passes through a hole in the eave (through a pipe flashing boot). Is there any reason not to do the same with my antenna mast (besides the obvious nuisance of having to drill a hole and do some roofing repair)?

Is the gap from the side of the house to protect the house from lightning strikes? If so, why don't service entrance masts employ the same protection?

Edit:

Thanks for the answer! Here's what it ended up looking like:

This does make things a little more complicated:

1. You have to run the feed line inside the mast / conduit, otherwise the rubber boot on the flashing doesn't fit right
2. Since the cables are on the inside and it terminates in a box, I have to prevent rain from coming in the conduit.
3. Since the N-connectors are too large to fit through the holes in the weather head, I had to cut off a connector, feed the feed line through and then solder the end back on again.
4. The weather head interferes with the ground plane rods on the VHF / UHF antenna.

Answer 1

I know that the gap between the wall and the antenna mast that would be created using the wall mounts you mention is not for lightning damage prevention purposes. If a bolt of lightning can travel hundreds of meters from a cloud to the ground, another half-meter of air between a mast and a building won't be much of a deterrent, especially when the bolt could follow the feed line to the house.

I strongly suspect that the 18" (46 cm) spacing that those brackets would create is intended to allow the mast to clear an eave. If you have nothing against punching a hole in the roof, installing a pipe flashing boot, and repairing the roofing, then I'd say that there is no engineering reason to not mount the mast directly on the wall.

As always, do be sure to take measures to protect your house and your station against a lightning strike.