TDC -how to use

[bech]

Hi all.
Quite new to in the TDC business.
In order to update the target bearing I do:
Use Attack periscope, point at the target - go to TDC: enter AOB - switch angle tracking to AP, correct?

Another thing: estimating the target range, seems like I continuously underestimate the range; ID target, (mast height / count number of centiradians) x 100 to get range in meters?
At what range can I expect to be spotted by the escorts, when surfaced at night, and same question for daytime?

Thank you for your support!