E3 visa transfer

I have a better job offer and wish to transfer my e3 visa.

The start date for my new job is 4 months away so I have time to file through USCIS. I am also planning to travel after job so don’t want to leave country twice in a few months so stamp option is best

WILL MY CURRENT EMPLOYER BE NOTIFIED IF I FILE NOW OR NOT UNTIL I INFORM THEM OF MY DECISION?

Also, if I choose not to travel, can I transfer again on the stamped visa or is this not allowed??

Thanks