Yep, you should be able to use 43's with your frame.
I have 4 frames all with 73 head angles (as steep as you get) and on all but one I use 43 forks. There's plenty of clearance between the front wheel and the down tube.
I only used a 45 on one frame as the forks had mudguard eyelets... good for my winter bike... and clip-on mudguards didn't fit/sit on my forks.
Should imagine that 43's would fit most bikes, including Steve Bauer's Stealth Bike! http://www.retrobike.co.uk/forum/viewtopic.php?t=137478
