stiff + lower tension string = helps absorb the shock so ur hand does not feel as much (usually during a smash). stiff + high tension string = ur arm will feel every bit of the shot (mostly during a smash) on overhead drops and net drops and clears - you should have more control or at least a better feel for it at high tension compared to low tension on a stiff racket. drives and smashes - your arm will feel a lot of the vibration, might take some time to get used to it. however might lose some power at high tension compared to low tension when i say high tension, that equals anything above 26 lbs (good feel, good control) and low tension is anything below 24 lbs. (no feel, not that good for control but more forgiving on mishits. better for smashing unless it is under 22 lbs) personally i think 24-26lbs is ideal for rackets. power+control in balance
iono... the feeling you get when you hit a shuttle... i dunno how to put it in words. as for control, that's when the shuttle flies where you want it to fly within a certain degree of error. for example, i do better overhead drops with tighter strings than with looser strings. however, if i'm off when I hit, that means i will be off on where the drop ends for higher tension string. on a lower tension string, it gives you more tolerance in this aspect.
u should try it out at maybe 28lbs (if your racket can handle it) and then at 23 lbs and you should feel the difference =D