About mixing two differents steps of a progression

Hi everybody.Now Im at the point I can work tuck planche for about 8 seconds, but after 3 or 4 repetitions I feel fatiged and the quality of it is not good. Is it good that when I feel that, try to complete the 60 secs with straight arm frogstand or should I work more on my frogstand? I can do 4 sets of 15 sec neither easily but not hard too. Thanks

Move to advance doing simple things (ex. 3 sec x 10) and build volume with the normal version (4x15s after that).

Do also other training exercise like dips and rings pushups.

Try to enter an advanced planche from HS, I found it very helpful.

Thanks Felipe,really appreciated