Great topic George!
In my opinion, skipping the top hammer is significantly easier than getting it.
In fact, for intermediate level players who have an outside shot at having a break out game and reaching a kill screen, skipping the top hammer throughout the game might save them a man on average. That's because it's a very common mistake to climb up the short ladder without accounting for the fact that Kong could be throwing a wild barrel right onto your head while climbing the ladder (Level 5+), and with so many barrel screens to get through, this will often eventually happen to a player at some point during a long game. Once you get even slightly deeper into the game most of the time so that the majority of your barrel screens are Level 5+ barrels, you will want to learn how to safely climb up the LONG ladder instead of the short ladder. When done correctly, the wild barrel cannot hit you on this ladder and you do NOT have to cross through the kill zone at all where you could be hit by a bomb. You just turn right (skipping the hammer) and finish the screen.
Finishing the screen from here without the hammer is only slightly trickier. First, you need to get beyond Kong's ladder, which may involve waiting and potentially grouping a double jump, or vertical jumping between two barrels depending on when the barrel might decend Kong's ladder. Then, when approaching the top-right section of the screen, it's almost always correct to stop and vertical jump the oncoming barrel because you could end up with short spacing if a barrel above comes down the top-right short ladder right behind the oncoming barrel (a very common occurance, and sort of a rookie mistake to broad jump into this dangerous situation). Once you get that section of the screen down without using the hammer, it becomes safer and easier to skip the top hammer.
Now, Levels 1 - 4 are a slightly different story. You should still be able to climb the Long ladder on Levels 1 and 2 without being hit by a wild barrel although those wild barrels are random and it may not be 100% safe. My advice even to intermediate level players is to simply restart your game if you die on Level 1 or 2 barrel screens. Now, for level 3 and 4 barrels (3 screens), if you are running boards you will have to deal with the nasty wild barrels in the top section of the screen. On these screens, climbing the long ladder is NOT safe! You'll need to climb the short ladder and go for the top hammer on these screens.
You CAN be assasinated while you are in the air trying to grab the hammer on these screens if you time your jump poorly. (not watching Kong's animation closely enough) You can also face strange wild barrel situations while climbing the short ladder -- in general, if it looks like the barrel will bounce on the upper girder to your left, you should quickly climb back DOWN the ladder (very counter-intuitive) and it will bounce severely sharply to the right and over your head. If it looks like it will actually miss the upper girder and bounce onto the lower girder, then you need to quickly climb back UP, OR you'll need to quickly JUMP if you're already all the way back down because this one will bounce severely sharply to the right and hit you in the legs. For intermediate level players, dealing with stuff in this paragraph will be a challenge -- I consider the knowledge and skills necessary to consistantly deal with these issues to be very advanced level play, so if you get whacked by Level 3 wild barrels here and there just don't sweat it too much, it happens to everyone.