wouldn’t white be pretty noticeable and easy to target?

Honestly just hitting anything with a shell at sea from beyond point blank range was a feat in and of itself. This is an era where even 5% of shells fired scoring hits at 10k yards would be considered acceptable in certain conditions. And while the British reacting tot he force of leadership of Jackie Fisher were developing and working on gunnery at every longer ranges and all the spotting and control systems needed for it. But 1907 is still a transitionary period, previously it was essentially assumed that naval engagements would be fought at relatively close ranges, from say 2-6k yards.

That wasn't the end of the world as a single hit as on the Russian flagship at Tsushima could be devastating if it struck the command spaces, or penetrated armor into vital compartments or engineering spaces. But in the end pre WW1 naval gunnery at anything beyond point blank range was as much luck as anything that could be helped. Camouflage then wouldn't have been particularly useful at the ranges where accurate fire became a realistic expectation.

It also wasn't as if the ships couldn't be repainted in Haze Gray while on the cruise. All that would have been required was a spot to anchor up and 2-3 days at most to clear for action. The ships would have painted themselves, and then removed most additional wood furniture and fittings, along with many of the ships' boats, and generally anything else that might splinter or catch fire that could be done without.

We also have aa perfect example of an American Squadron preparing itself for battle far from home. Commodore Dewey was able to do just that on very short notice while in British held Hong Kong before the war with Spain in 1898. Between the 21st and 26th of April of that year the Asiatic Squadron went from its peacetime establishment, had several ships join it, distributed additional ammunition supplies, moved out of British controlled waters, and got itself to a war footing to depart for Manila.