We had several sunny days this week, the greenhouse got HOT which means the sun is above the treeline again, and the grapevine and other perennials suddenly have swollen buds ready to pop! So now is the time for a "final" pruning. (I followed the advice for northerners, to do 'preliminary' pruning in winter but wait for early spring for the final cull, in case you lose some due to winter damage.)
I was going to ask, why do they mostly prune back to just 10 buds each on 2 arms. Then I re-read what you said CarolynK - exactly what I needed to know.
One of the 'arms' is much healthier, sturdier and more vigorous than the other, but now that spring is near I see they both have buds (and more than ten). I guess I'll let each keep ten buds and see what happens.