Use somewes.com to retime the run. To me this looks like the 5:00.472 pattern: https://somewes.com/smb-time/?game=smb1&category=Any%25&console=NES&time_estimate=5%3A00.472&frame_rule_offset=0&lag_frames=0&axe_frames=0

1. same as periwinkle's answer
2. there's a google sheet in the Resouces section of the leaderboard called BBG setups. the usual delay is -7.12 (11 fr from the start)
3. u can get 4:57 with 2 frame walljump
4. if u plan to incorporate blazit in your runs, rule of thumb is that u have to be pushed enough into the wall in two A presses. you can save the optimal frame rule even with a forwards jump into the pipe leading to the warp zone
5. Kosmic's any% tutorial covers the former. what i can say though is that for the star block, usually when the block disappears for a frame as you hit and you can see the star behind it before it comes out, that's a good sign that you saved bad judges