No problem running 740cc injectors in a NA if they are good new injectors that flow properly and you get the proper tune for them. The TT idles perfect and low speed is perfect when correctly tuned. If anything the NA would require more fuel than a TT at idle because it has higher compression. The original injectors for the early cars are single pintle. The newer Style 740cc Injectors are multiple hole pintle-less injectors. The 740 newer style spray pattern is better than a 370 single pintle spray pattern at the fuel required at idle for the Z engine. Since you are converting to TT, it makes perfect sense to upgrade to 740cc injectors now and use them in your NA. From my experience I would stay away from the Jecs and DW injectors being sold for the Z, they are bored out smaller injectors that are problematic at best.
