The period almost iconic set up for the HW35E was the Optima 3-9x45 Moonlighter. HW80 then the John Darling 3-9x56 Super Moonlighter.
Mounts is more tricky, but the Apel one piece with HW arrestor stud is the one to have. Rocking horse poo. Sportsmatch will do mounts for it with arrestor stud, though there might be others that do the same. Thing is many mounts are a bit modern looking for what is a vintage rifle in looks. Moderators don't look that good on them either.

Because the HW35 has been around forever then people have done all sorts of things. Nikkos, Tasco, Simons, and a bunch of others. The HW35 is on the chunky side so can take quite a bit of scope. 3-9x40's don't exactly "fill" the look, nor do the 2-7x32AO Tascos.

It takes a well fettled HW35 to hit a Polo mint out to 30m, and x9 will give a wood pigeon head shot sight picture for that.
Stick a 4-16x40 on and at high mag going for nat accuracy will just send you nuts. They were never meant to be benchrest rifles.
Range around the farmyard was just by getting familiar with the rifle and its drop. (The Moonlighter soon came with a BDC, but it wasn't ever that great so few people actually used them.)