The issues of how flaccid a penis should be while being stretched is a little tricky.: Everybody has their various views. Here is my view.
(i) You may pull on a totally flaccid penis only to a ‘super maximum’ of 85% of its full-stretched –capacity.This is warm-up.
(ii) At full stretch there is a moderate need for a filling up of the CCs so that the clamp effect of your grip is counter balanced by the pressure found in a blood-carrying CC. By so doing your penis tissues is protected from the mangling strains capable of being inflicted on a totally flaccid penis without the cushioning effect of a slightly plumped CC. So the idea is to get the pressure in the CCs and the pressure of your grip to Zero out each other thereby, reducing pressure on the point of the grip by distributing the pressure along the CC chambers.
(iii) Pulling on an erection is asking for an injury so know the limits. The idea is to tilt the scale a bit. If we all agree that one must achieve plasticity for growth. We must also prepare for a regular gripping of the penis above the gland. Gripping an inch above the head of a totally flaccid penis may be considered as harmful. Most times the extent of force being generated from the tension is being transmitted to the very nearby gland. However, with a cushion, the story quite different.
I guess its yours to make your choice after a test.
Regards
Infinity