From a purely visual perspective, I think this particular design would be better using a normal bertha-length tube rather than a baby tube.

These bashed designs seem to fall into specific categories.
Either they are stock big bertha/baby bertha with original fins but different color/markings to LOOK like a bash (like some of Sandman's nifty creations), or they are totally revamped with the only original parts being a stock tube and cone (like some of Excelsior's ).

Oh, another Rocksim weirdity. It didn't like fins hanging off the aft end.
It defaulted to rocksim calcs as Barrowman and Cut-Out couldn't handle it.
The drawing window had resizing issues too. Everytime I came out of editing a part, the drawing would be so huge that only the cone showed onscreen!