Just a question on swing weight.

I recently was able to hit a heavy swing weighted driver, D5 and I was amazed how my swing just fell into place...I seemed to have been very comfortable in this swing weight. Even if I tried to swing hard at it, my swing still seemed to be very stable. Then I tried it at D6 and 7, the driver started to hit the ground before ball impact, brought it back to D5 and perfect feel again.

is there such a thing as being comfortable at a certain swing weight?

Is it a smart thing to also do with the irons too? maybe trying D3 or D4 or even D5 with the irons an see what happens.

Is there another way to increase SW without adding too much lead tape?

Thanks so much!