Here is how I do a Sherman:
First I put on a light coat of OD on the wheels and Bogie parts and assemble them, the black for the rubber can be done after assembly.
After that i build the lower hull, uper hull and turret as seperate sub-assemblys and hit them with a layer of OD. As for the pioneer tools, you can add them right away using tiny drops of glue and then slip paper between them and the vehicle to paint them after spraying the OD or you can leave them off paint them seperate and attach after basecoating. I prefer the first method.
Now I combine the bogie assemblys (6 of 'em) and the lower and upper hulls into the complete hull.
At this point there should be a hull assembly and turret assembly.
I then do the final coat(s) of OD, paint the rubber part of the road wheels and paint/add the tools, Tracks are painted and added and weathering is done.
I don't prime figures but it seems most people do.
Tamiya XF-62 is one of their flat paints.