Sorry, no experience on this.

It seems like a simple experiment that shouldn't take long to perform.

• One packet of seeds. (Wheat grass sprouts quickly.)
• One small bag of potting soil.
• Two identical pots.
• Shelf space location allowing identical lighting for two pots, or rotate pots if nonoptimal lighting.

Soak some (10?) seeds in saliva, some in water. Plant seeds in labeled pots. Water. Wait. Record results on a daily basis.

Did the experiment confirm the hypothesis? Even if not, repeat until you're satisfied that saliva helps or hinders. Then try a different kind of seed.

Lather, rinse, repeat.

I can't imagine putting saliva on any seed. I wonder what type of seed you have in mind?
Most plants have developed the best way for their seeds to grow without your saliva, which was never part of the equation!
I admit that there are some seeds that can do with help to increase the percentage of germination. The lupin seed has a hard shell (about the size of a pea) which will have a better chance of germination if you nick the shell. Makes it easier for the shoot to push through the crust as it grows.
There are seeds which benefit from soaking in water over-night lke the anemone, but normally, the nature has it all planned for its seeds.
Just look how many acorns and sycamore seeds start germinating without help. I'm always pulling them up out of my garden otherwise it would be a wood pretty quickly.
In other words, don't waste your spit...