Hi Randy,
You are going to have an awesome car, that's for sure
You will find the body panels and dash have plenty of extra flange area to trim for fit. The extra area is left over from the molds. The excess flange also protects the parts in shipping, and during the assembly process. It leaves the final trim to fit up to the builder, so it's all good.
To expand on your Dash Fitment question, and I may be repeating this advice if not, hears how I approach installing a new set of body panels and dash:
a)
Pretty Much Essential: Block the chassis off the ground at your desired ride height - then fit all the suspension (less coilovers, sway bars) with brake discs and tires mounted with close suspension alignment is the best way to make sure the chassis / suspension is correct before you start permanently mounting any body panels.
a) Leave the dash to last, the roof spider sets all the body panels
b) Be careful and do not over trim flanges
c) Set roof spider on chassis. Check for initial squareness across the chassis and on the cowl. Some extra flange width can be trimmed back so as to not interfere with door fitting but leave as much as possible of this flange for the weather-strips. Also the flange at the lower windshield opening to the cowl top may require some tidying up.
d) Loosely fit the remaining panels, both doors, sill panels, front and rear subframes mount the nose and tail clips, set in center hood panel. These parts can be temporarily held in place with clecos, duct tape, lifted with foam board strips wood offcuts to align the gaps and shapes between panels. The front and rear clips can be supported with jacks or blocks of wood if you're not ready to tackle the rear hinges and front bobbins.
e) A "happy place" where all the panels line up and gaps are as close as possible will become apparent. As the roof spider sets the rest of the panels, it makes it possible to confirm the location of Fuel Filler Caps on the front clip. The location of the sill panels matches the front and rear clips. This also gives an early indication of wheelbase / wheels and tires / wheel well opening clearance and symmetry.
On the matter of "symmetry" the body has to fit the chassis not the other way around. I've seen cars with a different wheelbase on each side in an effort to match up wheel openings. Do not do this.
f) Trim the dash to fit, keeping a close eye on the leading edge of the dash with the windshield to cowl area and the interior door gaps.
Everything will line up, it takes a lot of fiddling, off and on, off and on, off and on but it's worth it in the end.
Looking forward to following your build
Cheers
Ian