Burning base with cable clamps

Have been clamping irregularly for the past 5 years with a circular homemade clamp rill recently I was able to import USA made cable clamps. Put them to use for the past 3 weeks and have couple of questions.

1) Noticed a burning sensation at the base after passing 8 minutes clamped. The glans still looked pink and yet to be cyanosed (bluish or purple). Should I go past this burning sensation and clamp until glans become cyanosed (after 12-15 minutes)?

2) Notice a bunch of veins protruding out right below where I’ve clamped. Is this normal?

3) Do you guys usually clamp until the very last click or let 2-3 clicks loose?

4) Finally, I have these bothersome sclerosed lymph veins right below my glans. It just gets worse with girth work and vacuum based extenders. Should I just continue clamping ignoring them? Noticed them getting bigger day by day, will they one day affect the proper function of unit too?