Swim Cap Extenderhanger

In last few days I’m experimenting with swim cap extender. I can wear it for 1h or more but I don’t wanna risk that much since I can’t see my glans.

After 1h I get marks on glans which disappears after 5 minutes max so I think it’s pretty much good. Anyways I have few question:

1.What force should I use for extending? I experimented wit 700ml of water.

2.How many hours to wear per day and how many days per week?

3.Is it less productive if make pause between 1h sessions?