Both striker timing and wicket chance are on 50-60, I haven't noticed a big difference other than maybe wickets feel a little more "earned" on the lower setting.
My player is a fast-medium around 130-135 kph, strong inswing and outswing.
I think it's a little of a false dichotomy to say mixing it up vs. bowling to a plan. The biggest thing is variation within a plan. Aftertouch and minor changes in jump/release are vital. If you bowl four front-of-good-length outswingers on 6th stump line and the next one is a back-of-full inswinger on the same line... that's when you get the wickets.
I have a few typical deliveries that work well at achieving the line/movement I want, to get the batter playing, usually aiming inswingers and outswingers between top of off and 6th stump, back-of-full or front-of-good-length, with aftertouch based on how the over is going. if I sense the batsman getting comfortable, keep them honest with a short ball / cross seam / yorker. For limited overs where they will be looking to play shots, can pitch farther outside and aim for catches (slips or in/outfield); or limit runs with front-of-full / yorkers. Control line, try to avoid giving them easy leg-side shots. Standard cricket stuff.
I usually don't aim for any specific mode of dismissal, but try to hit the block hole a decent percent of the time and good things happen.
The above applies to my bowling to a right-hander. Still working on a decent plan for lefthanders, moving to a wide over the wicket run up and pitching inswingers a bit further outside off.
Things you should vary:
Seam angle - Adjusts the swing direction of the delivery; for seam balls, can change how the ball bounces (I think)
Jump angle - Adjusts how much the ball moves -- e.g. for outswinger to the right hander, jump at 5'oclock angle will make it pitch straighter, jump at 7o'clock will curve it more.
Release angle - Which way you 'push' the ball out of the hand, has biggest impact on line. Usually you will have to push an outswinger into the batter and vice versa.
Aftertouch - Fine tune where on the pitch the ball will bounce; allows variation within an over to find the edge
Run up angle - for lefthanders or other strange situations
@Gamer Pradosh video was very helpful. You can see how using minor variations of aftertouch and jump/release angle, you can achieve precision around the stumps. Especially note how to use jump/release angle.