"...the dial is Gen, but I Think is too small for the case opening."
The harsh truth is there is not much of a fix for this.
When a dial is too small...
First, the dial paint at the edge of the dial gets chipped.
Then a chunk of an hour marker or dot gets scraped off.
How?
By the movement/dial sliding around in the case when setting time, winding the watch, or screwing the crown down.
What is the fix?
A precision spacer and stout case clamps/screws is sometimes a half-azz fix...but if the dial is too small, it will always show.
"the movement needs service and I have a few spare parts for it."
"ETA 2893-2 GMT"
IF the dial is genuine for sure, maybe find a properly fitting case first and go from there because it would probably be worth finishing.
Another thing is the 2893 is a fine movement but with 28800 BPH, it will be easy to tell the watch is a replica, especially if anyone handles it and finds the QS date and adj. 24H hand. Fine for a 16750 etc. though.
But that would be another rabbit hole. Ha!
I've been down this road quite a few times and ill-fitting projects hardly ever/never turn out right. All the parts have to fit reasonably well to start with.
My 'shortcut 1655' fiasco is a good example.
Where is it now?
Case, dial etc. is in the project/junk box. The Rlx 1570/75 is in a 34mm 1002 'explorer' project watch. Leftover parts are in a little tin can.
How long did it take to 'complete' the 'SC 1655' project?
Probably 100+ hours counting movement work etc. before I decided to put the movement in the 1002.
If it ever comes back to life, it will have an ETA 2846 with a non adj. Asian 24H setup. I'll leave it a QS but remove the 'second notch' QS position.
One major problem I never could get past was it just never looked right.
But it looks good 'nuff for a 2846.
Good Luck!