Clarification on Shabbat Timer

Question

I would like to clarify the followings regarding timer on Shabbat. I have a battery powered digital timer used for Shabbat. In order to change the time, I have to press the “mode” switch a few times to get to programming mode, then I have to press “on” and “off” switch to get to desired program, then I can increase or decrease the set time by pressing the increment switch. Pressing any of these switches makes internal circuit to draw a very small electric current, to be able to sense what you pressed. Based on this would you please answer the followings: 1-The light is on, is it permissible to change the setting in order to turn it off earlier or later? 2-The light is off, is it permissible to change the setting in order to turn it on earlier or later? 3-If the answers are no, what about Yom Tov? 4-If I have a delay switch meaning that when you press, it is not going to activate the light right away, but it will after the delay is over. Here too, pressing the switch will cause a small electric current to be drawn. Is it permissible to use such a switch on Shabbat? 5-If the answer is yes, does it matter that how long the time delay is?