New jets needed?

Just finished installing my new Summit 600 CFM carb with electric choke and Weiand Action Plus 4 BBL intake.
All is fine at idle and mid to high RPM but I am getting a hesitation at take off.
So far I've adjusted the air/fuel mix and have maxed my vacuum at idle and have adjusted my curb idle and timing to about 800 RPMs.
Is the next step looking to rejet the primaries to get rid of the hesitation?

Also, on a side note, my car shifts out of 1st between 15-18 MPH... is there an adjustment to make it shift alittle later?

Thanks,
Clark

PS on the Summit carb.... I really like. Easy to adjust and seems to like a quality product!