[C#] Issue with calculating transform.position and Vector2D

Im trying to make a spawner which spawns a line of prefabs depending on the number chosen in the editor. I know that transform.position gives me the current location of the spawner, but I need to add the width of the previous spawned sprite in order to make the line of spawned prefabs.

The issue is that it says I am not allowed to add transform.position with Vector 2D.

What Im trying is:
spawnPosition = transform.position + Vector2(0.25, 0);

Use Vector3 instead.

spawnPosition = transform.position + new Vector3(0.25, 0);

And look at Sprite.Bounds (rect) to make sprites sequence accurate:

spawnPosition = transform.position + new Vector3(mySprite.bounds.size.x, 0);