I have the stove top next to the refrig's.
I light a burner on the stove first. Sometimes takes a couple of minutes to get the gas from the tanks to the stove top (I use a striker lighter (the one's with the black long barrel and the butane in the handle)).
Once the stove top burner gets good and stable, THEN I turn the refrig's on. Seldomly takes more than the one start attempt of the refrig's. The distance from the stove gas T (where I KNOW I have good gas pressure and fully gas in the line (ie no air)) to the refrig gas T is about 5'. Takes about 2 - 3 seconds until a strong enough gas mixture (ie purges the air out of the refrig line) gets to the refrig's for the refrig burner to light.
Just an idea, your setup may be completely different.
Bob Weis