The other day I tried and exercise that they say is very useful for 1 arm FL, and it is 1 arm FL raises with band, but it was incredibly difficult, even with the thickest band I had to use one finger with my other hand to help, so to get stronger in that I'm doing weighted Front Lever raises today I tried with 5kg, and I did 9 reps and 10kg 5 reps also I try to add a little bit of pause on the FL position I want I see if this helps with the 1 arm FL progression, also I may add weight to my FL hold I don't think there is much point on in increasing the seconds over 30s, now I have 28s FL so increasing it will manly increase my endurance not my strength which is what I need to get the1 arm FL.