Depending on if your car is lowered and what size and type of rear tire you have, will greatly affect what front skinny to run.
If lowered, the 26" tall will slam the nose and possibly scrape piping if FM IC on hard braking.
If stock ride height, the 26" is acceptable.
If you are running a 27" or 28" diameter rear tire, like a 255/60R-15 or a 275/60R-15, run a matching 27" or 28" tall tire. If you run a 26" front with a 28" rear, the car will have a severe rake that can hurt weight transfer on hard launches if the suspension is not properly dialed in.
If you have radials on the back, the M/T SR radials and their regular Sportsmans are typically used for street use. However, you will occasionally see these tires run with bias ply slicks at the track, but it's not recommended.
If you plan on running bias ply slicks or DOT bias ply rears, you have more options from M/T and Hoosier for 26", 27" and 28" skinnies.
275/60R-15 drag radials, I recommend a 28x6.0R15" front skinny. Also, I personally like to keep the diameter the same on stock ride height Turbo Buicks.
These next picks all show same diameter bias ply tires all around on skinnies and 10's on the white car (RARE T) the blue car (SARAH) and the gray car (RU). Skinnies and 8's on the GN (LEGEND).... for now.
Hope some of this helps.
-Patrick-