OK, I'm having trouble seeing how much more dangerous a 1911 is just for the fact that the safety is taken off at some point early in the draw.
Granted, the safety will prevent dropping the hammer no katter how much one may squeeze the trigger, but that's it...it ONLY prevents one from dropping the hammer IF one squeezes the trigger.
There are scads of guns on the market today with no manual safety like the one being talked about here on the 1911. And yet, somehow they're drawn with no problems.
The 1911 won't fire from Condition 1 anyway until you've settled your grip sufficiently to depress the grip safety (that drop safety the U.S. Cavalry wanted).
There will, however, always be those who will debate the issue of exactly when the manual safety should be disengaged.
Here's my opinion:
First, as a lefty, you should get an ambidextrious safety and install it. Just do it...take the issue of the inconvenience of a right handed safety with a left handed shooter OUT of the equation. If nothing else, it'll stop you from fumbling around with unnatural hand positions trying to find an easy/convenient way to engage and disengage the manual safety.
THAT is arguably more dangerous than exactly when the safety is disengaged. Any time you have to do compromising hand movements you increase the odds of losing grip/finger control of the weapon.
As for cost...how many boxes of ammo would you run through for the price of replacing the manual safety? Put in this perspective, the cost os negligable.
Second...regardless of when, exactly, you release the manual safety, PRACTICE it. Pay intimate attention to each and every detail of your draw in slow motion until it becomes "natural". Get it right in every detail, every time, as you practice.