[Boatanchors] Antenna relay questions

[bc at councilman.com]

I'm about to hang a ladder line doublet and looking for an easy way to keep it grounded when not in use.

Expect to run 300-400 watts SSB, but someday might get the Loudenboomer going.

Palstar AT2KD via 5' of coax to a 4:1 balun mounted in an enclosure on an exterior wall.

I'm planning on using a traditional dow-key relay to keep the peace between a 75A4 and a CE100v/600l combination.

Any reason not to use a second dow-key at the balun to ground the antenna?  Or do I need something more substantial?

I've been away from the hobby for 50 years.  Is there a better solution?

As always, your help is much appreciated,

-Brad  W1BCC