Boards are for working your sticking point, and overloading your lockout.
Bands are used in the same way that chains are. The only difference being that bands pull you down on the eccentric. Also bands are much rougher on your body...so for bench work it is best to only cycle them in for 2-3 weeks...then go back to chains. You can also use chains for the lightened method. Choke the band at the top of the power rack and suspend the bar in it...with this set up 135 should be pretty weightless at chest level...so it helps at the bottom but lets off at the top.