It's now looking like an ideal working SB45, and better than when it was new, due to the vastly better engine. The chaincase looks like new, which I'm not used to seeing. We haven't seen a view of the catcher, so we can critique your panelbeating on that. The Briggs is visibly a modern one, but I think that was your plan. The front roller looks like stainless steel, which is highly functional but not original. You might consider restoring the old Kirby-Lauson and putting it away safely so your heirs and successors can put the machine back to original condition. Other than that I personally can't fault it, it's an impressive restoration.
