According to Chaosphere's Frame Data Conclusions (extrapolated from the somberness frame data) it's a 17 frame gap between the d1 hitting and the smoke bomb hitting. According to Somberness's frame data, Smoke bomb leaves smoke's hand and is uninterruptable on frame 14/19. This means that if Smoke does d1~bomb, you have 12 absolute frames to interrupt, meaning there's 6 frames for you to input a 6f poke in order to completely interrupt Smoke. No smoke is going to risk a point blank smoke bomb after d1 barring a random check though, so you can expect to have a much larger window to punish his surely incoming d1, d3, d4, or b23, all of which leave him negative on block (with the exception of d4)