Personally, I have found that my own 124 prefers a diet of Falcon Accuracy Plus. They only weigh 7.3 but shoot nice and flat and are made by JSB.
When I first managed to track down the 124, I decided to fit a "period" scope to go with it. Something along the lines of a Jap' Tasco 4x32/40 AG goes well if you can find one. They sometimes come up on here so keep your eyes open while you wait for gun to be sorted!
Dont forget that you will need to get hold of a decent mount with the lateral arrestor pin to suit the FWB receiver grooves. Sportsmatch do a nice one piece mount to suit, an example of which I actually have on my 127. My 124 has an Ian Jones sourced Apel one piece.
Good luck and keep us informed of any progress. It will be worth the wait and expense!
Andy