TQ question

If your going to use a aftermarket dual plane, then my two choices would be a Weiand Action Plus or a LD-340 that has been carved to adapt the TQ to fit.
The 2 single plane intakes would be a Holley Strip Dominator or a MoPar M1 single plane.

Would the single planes have a weaker vacuum signal?

The low vacuum signal should be addressed with lighter springs on the center rod.

And would this help make up for it?

The car would NOT be a daily driver.....more of a car show thing and a tear-em-up toy. No strip time, likely, either.