[mariner2k]

I am going to be replacing a rotted main mast on my 45' ketch. The current mast is a box mast with a single spreader rig. The replacement is the same height dimension. (45') The cap/pully and gooseneck measurements are perfect. However the newer mast is a round mast and a bit less beefy. (about 8-9" diameter at it's thickest point) It was originally rigged with two spreaders.
The question is: Do I need to keep the double spreader arrangement or can I rig it identical to the original box mast?
Once again the major difference between the two is one being a box/oval (rotted mast) and the other being round. Also between the two boats, the round mast had a 20' boom and a much larger mainsail, with about the same headsail area. The existing box mast has a 16' boom leaving a much smaller mainsail area. In other words the newer mast will be carrying much less sail area than it used to carry. Is there a trade off?
Thanks, Kevin

In addition, does the dimension of the mast matter as much as the geometry of the rigging?