I have zero synchro problems. I do occasionally strip the teeth off 3rd gear which is my only recurring transmission problem. I use the remote shifter and you use the long "school bus" one I think. That may be a difference.

I had one transmission that lasted a very long time. Several seasons. I was using a weak pressure plate that allowed a little slippage when shifting so I guess it didn't stress the transmission too much. One time when the transmission was out I pulled off the lid and looked inside. The nubs on the synchro's were almost worn off and the transmission was full of brass. Still it shifted like butter. I put in new synchros and used it for another year or so. Eventually the pressure plate and clutch got so bad that I had to replace them. Blew 3rd gear the next race from the added stress of a grippy clutch.

Those synchro's are silly expensive so I use good used ones. I dress the inside with a light pass of 600 sand paper. I dress the cone on the gears the same way. I think it encourages the synchro and gear to bed together better with a little use. I also check synchros real carefully for cracks.

What happens to yours? Bo they break apart or just crunch on gear shifts?

Yes you could shift in and out of OD with or without the clutch, but with 30W gear oil, mine used to jerk so bad when I hit the switch that using the clutch was necessary.

As for benefit...well if it bangs into OD like mine did, its probably doing more damage that shifting smoothly into OD (by using synthetic) and less wear on the clutch cable.
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...and the bricks keep on rolling