I built my own w/d also. I drilled 1/8" holes. My problem was that my drip plate fit exactly which sealed off the space underneath and created an air pocket. The water would backfill on the plate and then "burp/glug" the water down the holes splashing it all over. I thought the hole size was the problem. I drilled some vent holes in the side plate and problem solved. I don't know if you'll run into this too, but I thought I might mention it