The Hornet had an impressive performance , was used in operations after the war. According to Wikipedia the twin DB 605 engined push-pull Dornier Do 335 was produced from late 1943 in 28 preproduction aircraft and 11 production aircraft but no serious operations when war ended. It was a bit faster than the Hornet at up to 775 kph while the Hornet did 760 kph (Wikipedia numbers) , so you could call it the fastest prop aircraft then, not counting the modern heavily modified Reno racers, these non-series of course.
As to cam lubrication, one can debate what helps more, a hole in the Vincent cam follower contact face in hope for some rare oil drop reaching it once in a while - or a safe supply into the camshaft with a plain contact face and no hole to spoil the built-up oil film.
The SR /XT 500 hardchromed cam followers get an oil feed from a gear pump into their hole in the contact pad but you can clearly see on the worn cams the effect of the hole. Later they fitted a sort of "hardblock" material on the follower, undrilled, oil hole from the side like a jet onto the cam, a little better . My guess, the material of both mating components is critical, stellited followers likely the best bet ?? When the camshafts got bushes inside you have to make sure any oiling from inside can exit at any camshaft positions all around, so some grooving job will be required, either in the camshaft bore or with the bushes, not just drilling through the bushes by the original cam holes on the base circle.
The old Ford 2 l OHC engines had oil jet tubes all along the camshaft but still their troubles remained with cam and follower wear. My thinking is , not only a good oil supply will do it, but at the same time a suitable material combination is critical, as in times you have uncertain lubrication situations with some rubbing contact. In consequence I did some welding on followers with high chrome 55 HRC material which does it since many tens of thousands kms, sort of stelliting I think.
Vic
DB 605 vs. RR Merlin:
Dornier Do 335:
Do 335 after restauration by Dornier from 1974, returned to USA in 1986:
SR 500 cam follower hardchromed, a bit of wear:
welded Ford followers: