After trying both the stacked ply and solid wood, the plinth that jived with my 401 and the rest of my system was one that was based on loricraft's. Synergy must have been related to arm choice but it ended up being the cheapest to build. Except for having real wood glued to the top board by a wood craftsman i did the rest of the plinth. Total cost was around $50 (most of the materials i already had with me)
http://www.theanalogdept.com/rodney_eugenio.htm
http://www.theanalogdept.com/rodney_eugenio.htm