You see this is where my OCD comes in handy.
I made sure I researched form for hours before I started, and am constantly trying to perfect it.
I'd say it was pretty tight now, always controled.
Fairly slow on the lowering, and more explosive on the way up.
I have no advie to give seen as I don't have any lifting experience, but I will say this.
You might have seen the Hodge Twins on YouTube.
Now I don't belive they give very good advice sometimes, but they're big, and their response to an e-mail about rep speed, cheat reps etc;
Was "Just lift the f***ing weight".
Crudely put as always, but basically, as long as your not cheating as you say your not, and you're not lifting the weight at a ridiculously slow speed, your alright.
Deliberation over form seems to be endless, but really it seems to me as long as your lifting the weight with reasonable, controlled form, you can't go wrong.
You progress, get bigger, get stronger, so its working.