Sorry but an adapter can go in the checked bag and I am not worried about a baggage handler taking that. Did I ask you if you thought paying X amount of dollars is a smart buy for a reg? You have some other issues going on that you must jump in and offer no help whatsoever!
Can anyone tell me if using a Ti 1st stage and a brass adapter will be harmful other then 2 un-similar metals bonding. Which I have heard can cause rust faster?
There are dis-similar metals between most all Yoke/DIN adapters and 1st stages. My experience is you get enough salt water in the threads that when it dries, it is a sumbitch to get apart. In any event, neither will rust (FeOx) since neither contain iron.
The solution is to unscrew the two after a nice two hour soak (like after your second dive). Without knowing the exact alloy of the threads on your regulator and the body of the adapter there is no way to predict how much galvanic reaction (if any) might happen.
You comment about putting your regulator in your checked bag seems overly paranoid to me, and I don't know of any US based airlines that are weighing carry-on luggage, but you should be careful with weight restrictions on that aluminum foil hat