I guess TWT is more into Pl'ing than BB'ing? Anyway.....With a wider, or extra wide grip, you are placing too much of a work load on the the pec' themselves. They may be taking the undesired blunt of that work load ( strain,tear, etc) The joints may tend to become over taxed also with any extreme hand spacing. Where as, you want a almost equal balance of the pushing muscles of the anterior delts, triceps and the pecs for handling heavy weight and strength gains. You will generate more direct force/muscle action on the bar/bench press it's self with a medium to closer hand spacing. The joints also become more inline and supported by the delts, pec's & triceps when lifting heavy. This spares or saves the joints somewhat. With proper BP'ing mechanics the elbows should not cause undo concern. As suggested by HedgeHog, not too many top benches seem to have major elbow problems. At least the ones I come in contact with.
BB'ers will gain a better stretch and pec action with a wider grip, elbows back and lowering the bar towards the upper chest. Even to the neck area (Gironda style) but a much lighter weight and higher reps are used to avoid any injury.
The more reps/practice that TWT does on the closer grip the more he will readjust the responses of the motor units in the pec's, delts and triceps pushing motion. Training them as a almost equal unit, he should match that 405 he got with a wider grip before long. And probably push his BP much higher in the long run. He just has to adapt to a new and better style of benching. If WestSide say's to do this or that, maybe it's time to listen to them. Good Luck.
