RTV if too liberally applied can break off and get sucked back into the engine and foul the glo plug resulting in an immediate dead stick. Not so much a big deal on fixed wing but be aware.

As stated earlier, you really don't need anything more than clean surfaces and let the engine warm up enough to get everything up to temp then snug the bolts.

Locktite my make you feel better but most of the common brands will liquify under the heat and be useless anyhow.