Funny you mention a tight spring.....
For years I've used that DW Heavy spring on my Elim's and it's tightened to almost max (about 4 turns to the end I guess). The beater is back too, and I shortened the length of the strap and chain about a 1/4 inch. I also put one of those beater balancer weights under the beater head. The beater is almost to the end of the shaft.
They have a lot of action, and other friends that have lighter foot playing have liked it too.
I think the beater weight evens things out, because it's not a heavy feel at all. It's even on the stroke, and snaps back quick with the heavier spring.
Yeah, "flubber" is a good way to describe how it felt with the heavy rock band rehearsal. I just wasn't used to it, and was probably digging in too much. It only happened a couple times, but it was weird!
The 16 is full headed, and the 18 has been fine, but the 20" depth drums do better with a port so the sound is directly in sync with the bass guitar.
I had it unported, but on a recording of a show, I heard a tiny difference in how the bass guitar fell with the bass drum (we
were together on the show).
It was mostly the overall sound than the initial hit, so I went ahead and put the smallest port in. No problems since.
I wish they made a 3" hole protector like the HOLZ. I just put the mic at the hole, not inside. That's enough to keep the sound I want, and the FOH has an easy time blending everything.
On the 16" depth, there isn't any issues at all, and it sounds real cool through a PA.