This is a fork mount
That looks like I just need two of those for $90 each.
Never tried it ...says its not available till fall also...and for 90$ u can get a thule big mouth 599xtr
i havent tried any other products besides thule...i have a velo vise fork mount and as far as having to take the front wheel off it doesnt bother me ...it also gives me a little more piece of mind that my fork it clamped in... it may possibly be a little more stirdy...just my opinion.
note: i'm not fimilar with the BAT system so im not sure why you would need a 899 upright rack system ...unless the standard 599 tray would not fit your BAT cross bars.