There might be a problem flying the Inverza w/o the cowl as that cowl is huge and flying with it off could affect the CG to a point of causing problems. I would carefully check the CG with the cowl removed before I would fly it that way. In most cases I 100% agree that flying with the cowl off is a good troubleshooting method and it still can be in this case. I'd just use a bit of caution to make sure the CG is within range so there are no additional surprises.