Hi to all....Im new

Why is Levitra considered better for Diabetics my experience of them are there not as good / (stronger) the Cialis or Viagra

When taking Cialis (10mg) or Viagra (50mg) I do get an erection but with both tabs it could be stronger my doc has said that I can double up which to be honest I have not yet done.

If I decide to double up would taking them be more beneficial taking one tab an hour or so apart or both at the same time.

Any advice appreciated

g.