Pica T-28 B
I can answer two of your questions. I currently have one I am going to build, will measure the cowl for you tonight and email the size. I do believe it will fit in nicely though.
I have flown this a/c, both ful size and the model, and it is a joy to fly. Add retracts and flaps and you have a great looking scale type a/c.
I flew my first kit using a 120 Saito and it flew very scale like. I don't have any experience on the 170 so can't give you an honest answer.
Jim Ogorek
Ringoes NJ
USA