Front tire dilemma

I don't think a 15x7x4.5bs will fit on a Demon.
On my 70 DusterK,68 Barracuda combo,the BJ hit the wheel, and tore off the wheel weights.
My 15x8x4.5bs Wheel Vintique Rallys,required a fair bit of " adjusting" to the wheel, the BJ, the UCA,and the fender. There would certainly be no way anything but a steel wheel could be made to fit. And the 245/50-15 tire gently rubbed both the strut rod and the frame at or near full-lock.

Before you get your alignment done, get the Moog problem solvers installed, and Poly strut-rod bushings,and some decent T-bars and shocks, and make sure the rear of the car sits level,from side to side.
Ask your tech to set the ride height per the daymn book, unless the front gets higher than the rear..... we can't have that lol.The center of the LCA pivot pin and the center of the LBJ should both be at about the same distance from the groundplane. The pivot pin can be a little higher.
Also,ask him to max out the caster with .5 degree negative camber.Both sides equal/ no stagger.

The caster will sweep the UCA to the back, and maximize your clearance to the fender at the front of the opening..
And the Polys will limit the forward travel of the LCA during braking.
And the bars and shocks will minimize or at least delay brake and turning dive.
And the proper ride height will minimize forward motion of the lower BJ as the suspension cycles up and down.

Do not attempt to align the car with the rear of the car not level in the side to side . Do not jack the T-bars around to correct for a weak rear spring; you are just twisting the car up,and messing up the handling. Fix the springs.
Try those tires now.
If the front of the car ends up higher than the rear..... fix the rear. This is why I run 25s up front and 27/28 in the rear on my nearly flat rear springs, to level the car. Well Ok it is raked just a teensey bit.