depends on the ski. Some skis like volkl walls for example are whats called a symetrical or true twin tip. That means that they are identical front and back so if you were to mount them at true center (same length from back of your boot to tail as toe of boot to tip) they would ski and have the same dimensions whether skiing regular or switch. Most skis that are twin tips have a different dimension to the front and back of ski so mounting true center might not be the best way to center mount because they were designed to ski say 1cm back or something. Most park skis have two marks on them for the tech, one traditional (further back prolly what youre used to) and one progressive (where the ski mfg suggests would be the best place to center mount) for the tech to mount based off of.
Basically what im getting at is you could go in there and say anything. mount these plus 2 or back three and they will, but knowing what you like comes from trying it out and for your first ones i would highly reccomend just mounting them the suggested progressive stance. Its just about center anyway generally. If you havent had center mounted skis before dont worry about it, it feels kinda weird for a run then your set and they are a hundred times better in the park. When youre hitting a rail your boot will be over the rail instead of four inches in behind it because you will actually be on the middle of your ski and if you want to learn to ski switch it makes in infinitely easier. I think they feel much more comfortable all around personally jumps, rails, all mountain but powder can be trickier.
i wouldnt worry like i said it is a good transition youll enjoy it if you ski park at all.