I recently completed my manual clicker press using a Harbor Freight seal press model. I ended up using two 3/8" steel plates that measured 12" x 15" as my base. I then purchased a 1.5" plastic clicker plate from Tandy Leather Factory. Here is a picture of the PDF instructions that I used. I believe I got them off of LW. I tried to post a picture of the clicker, but for some reason, I am not too savvy with this new format. You can see it on my Facebook page or my BlogSpot in about a week.
Hydraulic_Cutting_Press_ShoeSchool.pdf