Starting position depends on the spin of the ball and on the height of the ball. If the ball is of net height and backspin and long, try starting close to knee height and swing up to the ball. Don't swing too far back for this one or you won't get the right contact for spinning the ball.
Net height topspin long, you start higher and further back.
As for ending position, your racket should be at around head height and a little in front of your head, but that can change depending on how much you lean forwards. (Advanced note)There are exceptions to this, like when the ball is coming into your elbow. In that case, you can end at your opposite shoulder if there's a lot of topspin (or above the opposite shoulder if you really need to lift the ball). At the end of the day, the forehand loop is a stroke that is meant to have physical variations so that it can handle all situations.
This video should help
https://youtu.be/mKFTcOtF58E?t=31
**********
If you are standing on an analog clock and 12 o clock is in front of you, I'd say 2 or 10 o clock is the timing.
(Advanced note)This can change depending on if you really want some bigger angles.
As for where on the ball you want to contact, that depends on whether you want to lift it, or if you want to send it forward. Go up against the back of the ball if you want to lift it. Go forward on the top of the ball to send it forward.
**********
Inconsistency in practice can be caused by a lot of things, like technical problems. Make sure you fix those technical problems when you practice. When it comes to games, the number thing that causes inconsistency is a lack of observation and adjustment. You have to understand that each shot is not the same and that you will have to personally tailor each loop to each ball on the fly. You can't expect the shots you see in practice to be the same as those in a game everytime.
If you don't notice that a ball is lower than usual, or spinnier than usual, you will miss and you won't know why. So step one is to observe the ball the best you can and see everything about it.
The next step is to be able to adapt your stroke to the ball. If you do see that a ball is lower than usual, you will have to lift it a little more, so you will have to change your racket angle and go up a little more. If you see a ball isn't as long, you can't lift up as much as before or else your shot will go long, so you angle down and go forward to compensate. Maybe you see a ball that does not go your sweet spot of your swing, so you have to move your feet to get the ball and yourself in the perfect positions.
*************
If you want to be confident, you have to practice being confident. Sometimes, I like to pretend that I am the world champion, and I go for every amazing shot possible. I don't care if I miss (I understand that it is part of the learning process, and so should you). When I do this, I get to practice hitting hard and I get the feeling for it, which builds my confidence.
Naturally, when you get better and more consistent at the stroke, you will become more confident. So, I guess you can try to get better and more consistent, and then you can try my method of pretending to be the world champion.
*****
In the end, none of questions required the knowledge of specifically a penholder with skyline. Anyone here could have answered these questions. Just make sure your questions are specific, and those of us here will answer to the best of our ability.