Either of you motors will be fine, mine had an RCV90SP and flew quite fast with this set up, with no noseweight, suspect you might need a bit of noseweight with the 90 sized motor. I think either motor will fit in the cowl though. Here's a pic of mine, standard film covering with the black stripes removed and invasion stripes added in film. Great flyer, shame it wasn't a bit more accurate in shape though.

Ian.