A tapered DS Mast allows you to more effectively depower the Main in moderate to big air.
Make sure that the shrouds and forestay aren't as old as the Mast too and if in doubt immediately replace them as they're relatively inexpensive to replace while your Mast isn't!
We're currently in the process of revamping and updating an early tapered Proctor Mast that came out of DS #285 and which we'll be using to make competitve an SLI DS #14028 that came with non-tapered oval cruising Mast.
Dave Keran won five DS NACR's since 2000 on #316 and Len Fiock won several DS NACR's over the years on #156 using the same early tapered Proctor Mast.
Jumper struts were very common on almost all fractionally rigged dinghy and keelboat masts given that most had wooden spars before the advent of aluminum spars in the mid to late '50's.
The thought or perception probably was whatever was good for wood would also be good for aluminum so jumper struts carried over for a period of time until the smart racers started to realize that the jumper struts added weight aloft, windage and didn't allow the mast to bend to depower the Main so off they came!
The tapered Ballenger Mast on #2772 BUBBA starts tapering about 6'0" from the top and tapers from an teardrop shape to about 3/4" diameter circle at the very top allowing only for a very small Main Halyard sheave and little else.
My older daughter Alison posted a video yesterday to Vimeo
http://vimeo.com/66536452 that's linked to the DS Facebook page of Dave Keran #13150, Dean Iwahashi #11023 and myself #2772 blast reaching Sunday on Lake Yosemite at 12-13 knots in 20-30 knots of breeze after the last race was cancelled.
Alison jokingly posted "that no Masts were harmed in the making of this video" but if you watch closely you'll see all three Masts moving around a bit as all three of us skippers reacting with rapid mainsheet trimming to the puffs and lulls as we zip across Lake Yosemite.
I hope to post photographs of the modifications and updates to our old Proctor tapered Mast that we'll be doing shortly.
Mike Gillum #2772 BUBBA