To create a direct vision M4A4, I first extracted the hood section from the Tasca DV M4A2. These welded assemblies required extensive reshaping to represent the cast type used on the M4A4 (and M4A3). This was best done off the model.
Once completed, this was positioned on the hull using a brass i-beam "sleeper." Much filling sanding later created this result:
As the M4A4 was Tasca's first Sherman, it was missing much of the finer weld bead detail. This was added along with the many markings inherent to the DV parts.
Because I was eventually going to build more than one DV M4A4 and because I wasn't going to do this again—the hull ended up becoming a master pattern for a Tiger Model Designs kit. You can find it here: http://www.thenewtmd.com/M4A4-Upper-Hull