This is surprisingly rarely addressed but is really simple. Good release aid use that does not interfere with aiming and execution has the least movement of the release aid within your fingers during draw and achieving full draw, and also needs to be the least resource-use heavy.
To approach the second point first – if you contort your hand into a position when you start the draw you will use a lot of muscles to keep that position and it will be unstable. This is especially noticeable in hinge shooters who have an exaggerated “safe position” when drawing the bow but can also be seen in thumb trigger shooters.
Whether you are shooting a hinge or thumb trigger, decide how many fingers you want to put on the release aid. This is done really easily by drawing the bow solidly and quickly without interest in anchor point or peep sight position but purely with respect to how comfortable you are with keeping the release aid balance within you fingers as you draw.
Once you’ve made this decision practice drawing the bow and anchoring with no movement of the release aid though you fingers, without caring how you execute the shot after that. For thumb trigger shooters you need to look at trigger position. The movement on to the trigger has to start with a movement of your thumb low down inside your palm, the fat part of your thumb in your palm must move in and up then the first joint of your thumb can bend to rest on the trigger. You are looking for a trigger position and size that allows you to engage the first joint when the skin and flesh is thinnest on the trigger so there is a bone to trigger contact. Start with the trigger tension set heavy. Get this position consistent and then lighten the tension on the spring until it is just heavy enough that you are absolutely comfortable that you can place your thumb consistently on the trigger without it going off but no more, this will allow you to have a full draw position which is comfortable and execute the trigger however you choose to.
For hinge shooters if you are using a safety catch then disengaging the safety catch similarly needs to have no effect on where the dot holds. In some cases don’t be afraid to alter the size and shape of the safety catch peg, but where that is not possible pay attention to the most controllable finger on your release (index finger) and learn the balance on that finger to give a consistent engagement with the safety. For those of you shooting a hinge without a safety catch I would advise you to set the rotation on the hinge heavy enough that you do not have to contort you hand to keep it safe during the draw. If you are using a thumb post make sure that it is not so far forward that you are pulling the release aid out of a comfortable position in you hand to get your thumb on the post. Again the release aid needs to be set heavy enough that you can comfortably and quickly draw the bow without fear of a misfire and always remember that full draw with a hinge is not just when the release aid touches your face but is actually a significant and conscious setting movement (generally a tightening of second and third finger which may be linked to lifting your thumb away from a thumb post).