In our club, we have 3 Kibler SMR's. The first done by an experienced kit builder. The second was built by an inexperienced builder, but got help from experienced club members. The third was sent to a custom builder. Obviously, the third looks the best, the first was very nice and the second came out nice.
These were all .40 cal. and shoot better than most rifles, custom or not.
If you feel comfortable, then....no problem. Or...do like the second guy and seek help, but you still can do most of it, with help from the more experienced. Or...do like the third guy and find someone to finish it. Wouldn't be necessary to use a custom builder, but more than likely, they wouldn't charge to much. However, a good novice kit builder, that's willing would not have any problem.
Most of the fitting is done and done nicely.
These are just out-and-out great rifles. Look good....shoot good.