I'm a firm believer in the KISS rule. That's the main reason why I do not think the added complexity (more moving parts) of a IFS front axle is worth the supposable better handling.
Maybe on a bus that gets lots of miles the better tire wear might make the added complexity of a steerable axle worth it. Since we do not wear our tires out before they age out... is steerable really an advantage? I have not seen extra wear on my lifting tag tires and I do not lift it unless I'll be making multiple sharp turns. I actually put my tag tires on the front at 5 years so I could inspect the insides of the four tires and since the tag tires had not been doing much this gave the front tires a rest by putting on the tag... 75 psi instead of 115 psi.
I think you will find the rigs with steerable tags have lots of weight on the tag axle... as much as 14,000 lbs. They also are pushing 24,000 lbs on the drive axle so do you really want to raise that to 38,000 lbs with a lift-able tag? Adding 6,500 lbs to my 20,000 drive axle is not that big of an increase but it is the reason I rarely raise mine plus they are only 44" apart. A steerable tag has all of the moving parts of a solid front axle and alignment requirements.
I doubt my turning radius is any difference if I raise or not. I pretty sure four tires with 20,000 lbs on them will slide the two tires with only 6500 lbs on them in a turn. I DO NOT leave my lifting switch turned on as it's going to raise the axle as soon as the tranny down shifts into 2nd even if I'm not turning.
This post is my opinion (free advice). It is not intended to influence anyone's judgment nor do I advocate anyone do what I propose.
Sold 04 Dynasty to our son after 14 great years.
Upgraded with a 08 HR Navigator 45’...