It's hard to say without some sense of what distances you're working with, and what the terrain is like. The standard 1/4 wave for 450-470 is 6", and with a drilled through should give you the clearance you need. I'll have to look at how much height the mag mount adds (I want to say 1/2").Alternately, how much height can you get away with from the fender top? (Subtract am inch for mount height, to account for bracket or lip mount)
Pattern wise, the 1/4 wave will generally be more omnidirectional,where a taller gain antenna is more of a squashed donut (more gain, more squish).
A 5/8 there would be no problem on the fender or bed rail at around 12", but I think the double 5/8 browning I have might be close again at around 36", though it's sprung so a little rub might be okay, vs if it hit close to the base on a roof mount. The comet 2x4sr is even taller, but it also folds...is folding it to park feasible?
edit: did some measuring; the browning comes in at 34.5", the comet at 39" upright, and about 6.5" folded (just under 6" at the base, but there's a little spiral in the middle, and it doesn't fold quite 90 degrees), and the midland mag mount is ~3/4". surface mounting a 1/4 wave looks feasible, or the browning on a fender/lip mount if you want the gain...from what i saw, it was under 1.2:1 swr across everything i've used in GMRS and 70cm. the main reason it's not on my truck at the moment is clearance for the work garage (smaller truck, so a ~12" 5/8 wave is just low enough, though i have a 1/4 wave on now).