Engine - Prop Combo...

Hi All,

   Still working on a Senior Telemaster, and am planning on using an
OS-61 for power.  After getting the wing mounted on the fuze, I'm
wondering if a .61 is big enough?  Anyway, my question is how big a
prop can I use.  Prior plane was a 60 size trainer, and I used a 12x6
prop, and it seemed to work ok.  Do you think I can use a 13x5 on this
plane/engine combo???  12 x 6 = 72, and 13 x 5 =  65 so power seems
about the same.  I'm looking for take-off performance, not top speed.
Maybe even a 14x5 if I found one?????  Can you go too far with this?

Thanks for any input.