Many thanks to BOTH John and Kostas for your constructive comments and suggestions. I know I have a LONG way to go towards perfecting my form, but you both made some very relevant observations.
1) For SURE the "wedge" style of shoe doesn't help me when doing this type of lift (or for squats), so I will either go barefoot or wear a flat-soled shoe when I do those two exercises. On the "up" motion I do feel that I could "sit back" more before I begin the pull, and thus (automatically) put weight on my heels--and then it'll be more easy to concentrate on "driving them into the floor" as I move upwards.
2) I don't feel like I am engaging very well in the glutes, especially on the down (eccentric) part. I understand the idea of "hip drive" on the UP motion, but on the downward it's as if I am taking "mini-steps" from the full upright position by a) slowly tipping forward at the hip joint, then b) bending the knees while lowering the BB close to the shins and then finally c) going down to a "squat-type" stance and pushing the butt backward, keeping the back supine the entire way. I think this (bad?) habit comes from watching a video where Elliott is teaching a 1st-timer, and pointing out all the "mini-steps" that should occur during the course of the lift. It was very enlightening and I learned a lot from watching it, but perhaps I am "over-analyzing" it now, or trying to dissect my own form during the lift, rather than just making it ONE smooth movement and NOT thinking about what I should be doing (step a, b, c....).
https://www.youtube.com/watch?v=tFnwEsqJABU
As Kostas pointed out, I REALLY do not want to use ANY more of the lower back than absolutely necessary, so ANY ideas as to how I might engage the glutes more would be appreciated. Again, looking at Elliott's video it seems like I should "tip over" at the waist / hip joint while lowering the BB, and THEN bend at the knees and go down, rather than doing those actions simultaneously...but what do I know?
3) I don't think I need to take a Sumo stance, but perhaps can go a bit wider with the legs and feet a bit more pointed outward. I have found that to be more comfortable when I squat as well, but I undersand the value of doing adductor and hip stretches, as Scott shows in many of his videos specifically related to deadlifts and squats.
In any case, I will try to make those adjustments and not worry about adding weight at this point. I feel that I COULD do more, but I'm old enough to know that it'll just lead to forming bad habits (or worse, get injured!), so if I need to take a step backward to get it "perfect" then so be it!
If you think my DL was crappy, wait until you see my squat form! It'll probably have some of you rolling on the floor with laughter!
Thanks again to you both, this Forum is such a great resource for me. Hard to believe I "waited" 50+ YEARS to start deadlifting / squatting!
Harley