Couldn’t drill as to hard , I ended up turning a stud out of silver steel inserted in hole squared up then tapping with b hammer on top of holder and it marked it enough for me to centre punch and then drill, fitted and finished.Can't you drill one of the blind holes out?
Get it in the correct place and drill the register hole o drill one hole I have done it
If the other ones swing without indexing, they won't take the loads one with a pin does.It is swings and roundabouts (that might be a peculiarly British piece of folk wisdom - I'd be interested to hear your equivalent).
On something without an indexing pin, you can set it to any angle in a continuous manner. With 40 positions, you have to step every 9 degrees in a discrete manner. Once you move it, resetting it is fast and repeatable for the multifix, but hassle for the other version.
There are some people who angle their compound at 30 degrees or 29.5 degrees (or, presumably, 27.5 degrees for Whitworth) when screwcutting. Think of the mental anguish they would suffer if they only had 9 degree increments.