I am easing my way into the world of high-end watched, and I've picked out something that is just within reach of my budget (approx $5K)...if I buy it used or grey market.
My inclination is to buy pre-owned from a dealer who is an authorized distributor and repair / service provider for this brand. I should be able to get it slightly cheaper than from one of the big non-authorized dealers who sell this watch with only an in-house warranty.
Am I on the right track here? How do the manufacturers treat watches purchased on the secondary market, but through authorized dealers?
You are on the right track, but the situation is not one that has binary considerations. It's not an "either/or" sort of thing. What is the right decision depends on your first settling on what watch you want to buy. That done, you can then canvas the marketplace and determine whether to buy pre-owned from a reputable seller or new from a grey market seller (GMS) or new and at a sufficiently good discount from an authorized dealer/boutique.
If you are buying pre-owned, the main things to consider are (1) the seller's trustworthiness and willingness to stand behind their claims of authenticity, and (2) the state of repair of
the watch they sell to you. (the status of all the other watches they have on offer or ever sold is irrelevant)
If you are buying from a GMS, the main thing you'll want to be sure of is (1) that they have a good track record with customer service and (2) that the watch itself hasn't sat on a storeroom shelf so long that the lube inside hasn't clumped up (if it has, it's because the seals/gaskets have gone bad, so you may want to have it replaced), but that should only be a concern if you are buying a watch that's long been discontinued or that was produced a few years before you purchase it. If you are choosing a relatively popular and fast moving model, that won't be a problem.
As for how makers deal with pre-owned watches, most of them don't in terms of sales, but in terms of providing service, they don't care. They will always service and/or refurbish a watch/movement that they produced. Some makers without question will restore any watch they receive back to "like new" condition; others will communicate with the owner before doing so. That tends to be a factor for folks who've deliberately had aftermarket mods performed on the watch.
As for whether you should or should not be able to get a lower price one way or the other, I suggest just doing the research to find out exactly what you'll need to pay. There are no almost no guarantees. If you aren't willing and able to haggle a discount from any or all three types of sellers, the listed prices are what you'll pay. Good hagglers, on the other hand, can sometimes get as good (or nearly so) a price from and AD as they can going with a GMS. Some GMSes will negotiate with some customers and some won't. Also, some sellers of certain pre-owned watch models don't offer enough of a price variance between new and pre-owned to make buying pre-owned worth it. It's all market research you'll have to conduct to find out just what your pricing options are.
What one thing is guaranteed? It's guaranteed that if you don't ask for a price concession, you sure won't get one. You may have to put more effort into it than just asking, but not asking will almost certainly yield no concession; it's very rare that sellers volunteer to give a discount, other than when they are having an advertised sale/promotion.
All the best.