The string will slow it down some, but I don't think it will be nearly enough. I think the Savannah is cut at least to center, if not slightly past.

I'd get the test kit. 53@29, with 125 grain points and a dacron string, will probably need 60-65 or 65-70 spine arrows, if you leave them 30" long for broadhead clearance. Depends on your release too--a very good release will need a heavier spine than a sloppy one. A well made high performance string (Dynaflight '97, 450+, 8125, Fast Flight, etc.) will generally bump you up another 5# or more in spine.

It's possible the arrows you have will work, but more than likely they will be weak. You might get some use of out them if you use some 100 grain points.

Chad