I've noticed the aiming to be pretty intuitive. There are a few ways you can shorten your overall draw length. The first way is by drawing facing more towards your target. Then the next way, if you have a bow that isn't too heavy of a draw weight, you can bend your elbow in and get a normal anchor point or you can anchor with your wrist. There is this belief that shorter bows aren't accurate out at distances or that they are harder to shoot and I find that to not really be the case. I can shoot my short bows well out to 60 yards. They are very accurate as long as you have arrows that flight straight out of them.
Also yes make one!! 55" is about the perfect length for a juniper bow!! 100% go for it. And hey using juniper branches also tends to work very well. Usually the top side of the branch has few knots and you can just turn it straight into the back of a bow. The tops of the branches also usually curve upward and it gives a great opportunity to use that as natural reflex! Also if you can't find anything that is knot free that is totally okay! I've noticed that as long as they aren't huge knots they don't really matter all that much. And also you really don't have to worry about violating growth rings at all because it's getting sinew backed. You just carve it out to your desired shape and sinew back it!
Boy does juniper make a great bow! I have one right now that is 33# of drawweight at 24" and shoots a 400 grain arrow 150 fps!! Juniper is really an amazing and underrated bow wood......not gonna lie I like it more than osage. Juniper is lightweight (which is a huge advantage for speed), smells good, carves like a dream, has almost no stacking, draws & shoots super smooth, and I would argue can make a better bow than osage. Osage is so heavy and takes more time for the limbs to move which actually significantly slows down an arrow.