Bypass OE ampmeter

Some one posted a dieagam on how to do this. Bypass OE ampmeter But he just said. 1 blk wire to the fuse box, 1 blk wire to the wiper switch, and 1 blk wire the the light switch. I think on the 2 switches would go to the red wire. The big question is where do i hook the blk wire in the fuse box. Now there is a blk wire w/ white strip in the fuse box. That goes to the light switch. If I'm bypassing the ampmeter. Why can't I just install a in line 20 amp fuse and split and go right to the 2 switches.
I also have an fuseable link at the starter relay. New cars tell you what each fuse is for. Radio, wiper, interior lights. In 73 all it tells you is the amp size. :banghead: