sliding door material

I am in the process of building the Generic Benroy and I am cutting materials for the cabinets / Galley.
Can anyone tell me if the sliding door material for the Galley should be 1/4" or 3/8".
The width of the channel is 3/8". I have never made sliders before, so I am not familiar with the play or tolerances required.
Also, the plans don't mention to put in the slider in the slot / groove before glueing the ends of the panel (attn Mike for the next rev..).
Can anyone tell me if the sliding door material for the Galley should be 1/4" or 3/8".
The width of the channel is 3/8". I have never made sliders before, so I am not familiar with the play or tolerances required.
Also, the plans don't mention to put in the slider in the slot / groove before glueing the ends of the panel (attn Mike for the next rev..).