When substituting cams, ie. exhaust for inlet or vice versa, the original sprocket for the cam being used is retained. However, timing is the issue here. The duration, lift, & overlap of the cam is machined into it already but, as you understand, the timing is what is sought to be controlled/changed. This is why adjustable sprockets are desired.
Before re-timing my cams, I checked the stock timing and was surprised it was not quite what the factory specified. Then, in attempting to re-time to my desired settings I find it very difficult to get it exactly where I wanted it and in the end I had to settle for "close enough is good enough".
At the time, aftermarket adjustable sprockets were not available so I decided my best option was to have the factory cam sprockets (both) slotted. This is hardened steel and easier said than done but I discovered "spark erosion" or EDM (electrical discharge machining) and managed to have them slotted using this process quite economically. I can dig up the drawing indicating the slot length & orientation if required.
Just a final note, this mod on a speed triple will make more power, especially in the mid-upper revs but the full potential will be stymied by the lower red-line of the 1050 motor.