when the PETARD was fitted to the AVRE's by the way some not untill loading on there LCT for D Day, matter of fact some crews had never fired there own guns untill they landed.
they did not have a Gun sight at this time
it was not untill 42 Assault Regtiment went to the south downs on & around 6-9 june 1944 (my farther was one of these) they proff fired the Petard and gun sight on the Downs then it was retrofitted in all the other tanks.
the AVRE manual that is in the museums is of the later version showing the gun sight.
Maximum range was about 80yrds or if like my old man bounce off the Glasis plate and said that was the fastest he went in reverse.
also intialy there were two fuses and they did carry them on D Day. the 289 which was designed for minefields buut was dropped.