7x7 vs 1x19

[osteoderm]

Double -check those wires... Flexible wire for running rigging is usually 7x19. 7x7 is generally too stiff for such use. If your standing rig is 7x19, change it. If your running rig is 7x7, change it.
1x19 wire will be smaller than similarly-rated 7x7 wire, which equates to less windage. 7x7 wire is easier to splice, whereas most wire terminal fittings seem specific to 1x19 these days. The heavier individual strands of 1x19 stand up better on forestays, as they better resist chafing from hanks.
Others here will surely have more pointed technical advice to pass along. Still, if the existing 7x7 rig is correctly sized and in good shape, there's no practical reason, IMO, to change to 1x19.
Personally, I think a spliced 7x7 rig would look better on a classy boat like an H-28 ketch...