Exactly, so the inline module would create the warp bubble, the radial nacelles would add a multiplier. Something like - each nacelle multiples the warp bubble size and factor by .75 in an additvie fashion. So two nacelles makes bubble 1.5 times bigger and "faster". Idk, the actual numbers could be played around with a little bit for balance, but after looking through the code it should just be a matter of multiplying the warp factor and bubble scale by the number. Going from 3.5 to higher sizes would just involve creating bigger "tube" that creates exotic particles. Long term, it would be cool to make the bubble configurable like a fairing.