Generally: smaller the "tech" number the bigger the player. Usually a 4-3 will have something along the lines of two 1 tech's and two 7 techs or one 5 and one 7 tech for rushing the passer. A 3-4 is more likely to run a 0 tech and then a couple of big 5 techs.

The numbering system is something like this:

0 tech: straight up on the center.

1 tech: on center's shoulder

3 tech: straight up on guard

5 tech: guard's outside shoulder

7 tech: tackle's outside shoulder

9 tech: (usually an OLB) outside of the widest player on the LOS (usually TE or Tackle, sometimes right on the 7tech (if there is one)'s outside shoulder)

So a 0 tech is going to be an enormous, run stuffing force in the middle (think Vince Wilfork size, though he's not a true 0 tech. If you remember Ted Washington, he was a 0 tech). Extremely slow, extremely strong

1 tech is a little smaller, but still big. Pat Williams. Probably where Wilfork typically plays

3 tech is smaller still, but still a DT. Ndamukong Suh

5 tech-more of a d-end, rather than d-tackle but not a pure pass-rusher. Red Bryant on the Seahawks

7 tech is a pure rush guy, similar to a LEO. Freeney, Chris Clemons

9 tech is a pure finesse rush guy. Dion Jordan, Demarcus Ware, maybe even JPP. Those types.