I own two Waterford 1200s from the mid 1990s. They both have(had)the same issue; barrel adjusters frozen into the braze-on cable guide. On the first frame, my local LBS had to drill, as I remember, to get the old barrel adjuster out b/c the former owner ripped the top of the adjusters off leaving the threaded part still in the frame. On the newly acquired frame, the adjuster are also frozen, but the top part is in tack.
So, my first question is: how can I get the barrel adjusters out with out resorting to drilling?
Also, when I installed the new 11 speed group set on the first frame, I found that modern barrel adjusters are 1 mm or 2 larger. I finally found one that actually fits, but its too short to get the full tension I need from the front derailleur to smoothly shift from the small ring to the large. So, I need barrel adjusters that have a smaller diameter and are long enough to get the necessary tension on the front derailleur.
I plan to move the group set for frame 01 to the newly acquired frame 02.
Any suggestions are appreciated.

I would hit it with a heat gun to expand the braze on and try and unfreeze it. I bought a cheap heat gun about 15 years ago and got more than my money's worth out of it. Used it just the other day when installing a headset. I heated up the headtube, but the cups in the freezer for a little bit and was able to lightly tap them in place. BB30 bearings, frozen seatposts, frozen bolts, it's the jack of all trades.

On that job I might try the other end of the temperature spectrum and try freezing it.

I bought a can of this Finish Line Chill Zone to help with a stem. I haven't used it yet so I cannot claim whether or not it works as advertised or is just snake oil. I am hopeful though.

Finish Line - Bicycle Lubricants and Care Products - Chill Zone?

I wonder if using in-line barrel adjuster is the solution here. Modern barrel adjusters tend to rub the frame and I have had a hard time finding ones that fit the braz on. Any Waterford owners that have upgraded to 11 speed encounter this issue?

Are the screws M5? Here's some classy ones:

www.paragonmachineworks.com - CS1013StainlessSteelBarrelAdjusterforThreadedCableStops

Thanks for the info. Yes, I need m5. The question : will they clear the head tube, see my photos. The darn braze-on gives little clearance.