Your 1lo-1hi-2lo-2hi, etc pattern is correct for all the two speed rear ends I've ever seen. If it were a range box within the transmission, chances are you'ds go through all the gears, shift ranges, and go back through them again. I honestly think that you could probably leave it in high range most of the time. Just because you have 8 ratios doesn't mean you need to use them. I am pretty jealous though
As for needing the clutch...I drove a bus with a New Process 534 (I believe) transmission....might be the same one you have. Like all those big truck trannies, it was unsycnrhonized so it required double clutching. Once I got a feel for the "sweet spot" double clutching, it was nothing to shift without the clutch...let the engine wind down here, give the throttle a blip there...
As for getting back into low range when coming to a stop...We had issue with that other bus too. If you have a countershaft brake (clutch-brake), you might want to try engaging that when you are at a COMPLETE stop. I don't know that that will help at all, but it's worth a shot. The other thing I would do is when you're stopped, let the clutch out in neutral. Usually this is the difference between clash and mesh in the reverse gear of most transmissions (I've yet to see a synchronized reverse...you are essentially doiuble clutching reverse). It's frustrating because the rear and is shifted by a motor that has no feeling. A hydraulic shifter for the rear end might atleast allow you some feel for the gears...anyway....try that and maybe someone else will pipe in with a suggestion or trick they've learned in their experiences if it doesn't work.