Back lever in half lay total volume?

[Martin de Jesus Ponce Robaldino]

Well as i have understood in all the things i've read here, is that for progressions of lever (back front,etc) i have to aim for a total volume of 60 sec

Does it apply the same when you are working in the half lay or the full lay progression?

for example, i can hold 1 or 2 reps of 5 secs max in full back lever, i don't think that i should work 20 sets of 2 secs, should i?

How is it suppossed to be managed total volume of straddle, half lay or full lay?

Should i go back one progression and working in more intensity/volume for obtaining gains in the hardest progressions, or directly work on those hardest progressions...?

Thanks in advice!