How to palladium plate in lieu of rhodium to tarnish-proof silver

I require to produce a protective coating on silver products that we make, protecting them from sulfide blackening in a volcanic environment (Rotorua).

Silver Anti-tarnish Strips

on eBay or Amazon

(affil link)

From the Pt group metals I would prefer to plate in a bright palladium which is more ductile in post plate forming than rhodium plate.

Using palladium ammonium nitrate, I would like to know what brightener I should use in the plating bath and any other relevant information as our current palladium plate is of a matte finish at various temperatures. The bath palladium concentration of about 5 grams a litre. Next step is to try gas agitation during plating. Rather than waste a lot of time trying different methods it would be good to get a quick answer. Was thinking of trying the brighteners used in nickel plating?

If possible text references would be nice.

Thank you.

Regards