The reality of timed turns is that they are suprisingly accurate.
One isn't going to be doing a 360, normally. Typical turns will be on ATC direction, say 20 left or right etc. That is about 7 seconds. You don't need a stopwatch for that - just count to 7 at about the right speed, and you will roll out on the '20' as accurately as anybody could have flown the desired heading anyway.
I never did timed turns before the IR, and every one I did was spot on, and most of the time (for the slight turns) I wasn't even using a stopwatch to time them.
Try it one day. It really works.