Hi Alvin,
Here's a suggestion you might try.
1. Clean the front and rear sights with polish remover, let dry, then get some white finger nail polish and with a tooth pick touch or mark a small dot/spot on the front sight (high point not top). And for the rear sight, mark a dot/spot on each side of the V or U groove near the top also. This will tell you when you have the top front sight even with the rear tops and it may be more visible in your aiming.
For #2,
That's the other main reason for using the left thumb to pull the hammer, as mentioned previously. This changes the action from 'double action to single action.'
