Just a heads up on the drop spindles, I'm only running 15" rims and my clearance is only 8" to the bottom of the front bumper using regular spindles. Now larger tires will give a great clearance but at 8" I worry about coming off rounded curbs and speed bumps hitting....my 2 cents.
20s on M2 suspension with drop spindles.
<a href="http://s103.beta.photobucket.com/user/rjinator/library/F100%20BUILD" target="_blank"><img src="http://i103.photobucket.com/albums/m156/rjinator/F100%20BUILD/IMG_0555.jpg" border="0" alt="Photobucket"/></a>
Hmmmm... Tricky question on what size wheel you can run.
Our truck is a 1950 F1 with a Mustang II front end with coilovers -
standard axle - not dropped. The Mustang II drops the front end quite a bit - not sure a drop spindle is required.
We've really struggled with the wheel/tire size issue - we initially went with 18's front & back with 255-45-18 tires - 27 inch diameter/10 inch width. That's a pretty low profile tire & it didn't work up front - hit on dips & rubbed (a lot). We put in spring spacers & jacked the coilovers up to the max & it still didn't really work i.e. couldn't be aligned.
I went even smaller on the tire this week & it fits - 225-40-18's - that's a very low profile tire.
There's a lot that needs to be thought through - measure, measure, measure & talk to to some real wheel/tire guys. A lot depends on the Offset so you can tuck them in under the front fenders.
Good luck over there. Our truck's stance with 18's up front (see pic).