Not true... The equal weight of the Jika rig falls faster than a jighead no matter the shape. It's where the line tie is that effects the fall on a jighead. Do as you please though. 
Care to bet money on that?
I'm willing to bet $100 I have a 25oz jig that will drop faster than a 3# cod sinker Jika rigged on a heavy tide day in Cook Inlet here in AK.
I don't care how you rig it a slimmer profile will drop faster than a wide brick style weight or a big round cannonball.
Especially in a 4 knot current on a minus tide day!
My prostaff have tested my jigs and they will fall faster I guarantee it!
But your not likely fishing heavy saltwater currents in deeper water like I am.
What's the biggest jig/weight they fish in your area?
In mine it is a 5# cod sinker with a 14/0 circle hook and bait.
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