They are definitely a different sound. There are going to be inconsistencies because they are a natural product. If the heads are fitting too tightly and binding on the shells, that will have a direct effect on the tone. I know, because I have a drum that was really tight and Rob had to make a special flesh hoop with an Irish calfskin. Once that was done, the drum sounded great.
Maybe try a really thin resonant head like a Diplomat and then tension the calf batters to where they feel good and then adjust the resonant head with the drum mounted until you hear it come into "the field".
Also, it may take a little time on the drum before the calf seats itself properly. I wouldn't recommend over-tightening them, but a fair amount of tension can be applied. Play them, they will lose tension. Add a little more tension...play....re-tension. Eventually, they will acclimate to the edges and then I think you will like them better.