I would glue before finishing. Glue doesn't like to stick to any finish.
If you are getting "squeeze out" of the glue, you are using too much glue. You can get a blob or two by using a toothpick to remove it but, it is easier to just put a thin film on the back of the cutting and apply weight on top of the stack. There usually not enough abuse to scrolling that just a small amount of glue wont hold things together. Also spray glue just on the back of the cutting might do it if you give it two coats and let it set up until tacky before mounting it.
Actually, if it is not too bad of squeeze out, it probably won't be noticed by anyone but you anyway. Sometimes even the finish (if you are spraying a hard finish coat) will help seal the edges and make the two pieces want to stick together also.
If you are "soaking" it in an oil bath before a final finish, you will have another problem with glue sticking things together.
Rog