Design center distances for rollers & V-slot extrusion?

I made an extension to 2020 v-slot aluminum extrusion the 2nd version match the drawing profile attached to this thing the long of this extension is 30mm ,

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2020 t slot It is also known under several generic names, such as aluminium extrusion, aluminium profile and 2020 There is a variation on T-slot profiles known as V-slot

2020 v slot extrusion SPECIFICATIONS ; Gross Weight: ; Made in: Portugal ; Series: V-Slot ; Profile: 2020 ; Length : 1500mm