Possibilities Without Moving Beyond Basics

Hi folks. I’m 4 months into PE now, been following a newbie routine as follows:
10 min. Warming with far IR pad at 100°F.
Manual stretch down, up, and to each side. Each stretch held for 30 sec.
Manual stretch starting up and slowly rotating clockwise downward over the course of 30 sec. Repeated rotating counterclockwise.
Manual stretch straight out held for 30 sec.
Manual stretch straight out and slowly rotating downward over 30 sec. Repeated rotating upward, then to each side.
Flaccid bends down, up, and to each side, stretched over the width of my hand and held for 30 sec. (I think these are called fulcrum stretches here)
Repeat the stretch “circuit” twice.
10 min. Warm down with far IR at 100°F.

At a separate time:
10 min. Slow jelq (3-4 sec. Strokes).
5 min. Gentle massage.

I do these 2 days on, 1 day off, 2 days on, 2 days off.
I’ve gained 0.375” on my BPEL (6.5%), and 0.5” on my MSEG (10%) in 3 months.

I have no desire to attach weights, or a stretching device, or a clamp to my dick for several hours per day, nor do I want to use a vacuum pump. All those things seem to raise the potential for injury drastically. Is it reasonable to expect if I continue with manually held stretches that I might gain another 5-6% in BPEL and 5% in MSEG over the course of a year?

The basics worked very well for me.