I agree with Matt about your draw probably changing. I'd really suggest getting a used bow to start with and get form down before going to a custom.
Below was taken from Black Rhino website:
The ideal way to measure draw length is to have the archer draw a light bow and measure the distance from the string at full draw to the back of the bow (the "back" of the bow being the side away from the archer). When a bow is not available an alternative method can be used. Place a yardstick at top of the archers chest right below the throat. Have the archer extend their arms and fingers out on to the yardstick as far as possible. The reading on the yardstick at the end of their extended fingers is their approximate draw length.
Another way is to take your compound draw (assumingdraw lengthwas correct) and subtract an inch which is about average from moving from compound to trad.