Lots of people will say to double your draw length and add 10" for a rigid handle. You are more or less in that area with your previous bows at a 27" draw (27x2 = 54 +10 = 64). If you picture the rigid handle bow without the 4" grip, you would be using the fades as the grip area (i.e. making it slightly thicker so it works just a bit). By cutting out (mentally!) the 4" rigid handle part, you would be at 60"...so you should be in good shape. If you have a handle that works more, you could go shorter. At least that's how I think about it...lots of better bowmaking minds here may have differing opinions (which I would like to hear)!