Suggestions for securing an x16 tightly to the wall? Adding rubber feet? Chucking the supplied wall mount extender screw and just use #10 screws on drywall? That method seems to be the best for me.

I've only install one on the wall. Just used a standard wall jack. No problems.

As far as the "wobble", they don't fit tight the only fix I've found was a shim on each side of the wall jack, or mount it to the wall with out the jack and just use molly's if you're not next to the stud, just as you stated. The shims work and you can break they so they're not visible.

Seems like a poor design for the wall mount application to me.

If we could use two x16 screw studs it would be great, but the wobble is pretty bad. Most wall phones grip tight to the wall phone jacks. I'm curious as to why their studs can't be made to hold the phone tight? I used my screw and anchor method today. It does the job but I'd rather not have to do that. Other manufacturers have had this wobble problem too and I just don't understand why it is so acceptable to them.

They put about as much thought into it as they did the spacing of the mounting holes to line up with the standard wall plate.

In other countries they used a different mount distance between the two pins, this system is made for use all around the world, they don't make it just for us.

It is the same for Samsung, a while back they decided to let the dealers all over the world decide what color the phones would be and we got the ugly, ugly putty "light black".

We may think we run the world but we don't and with the people we have elected we never will again.

I carry small squares of plywood smaller that the phone footprint.
Painted black or off white. Put on wall on stud or molly.
Short drywall screws hold phone using just holes on back of phone, adjust screws for a tight fit. Then a screw in the top back of phone angled so it touches top of phone where its hard to see.
No wiggle, no wobbles and cannot be remove without a screwdriver.
Doing mostly NEC and Panasonic. No way in hell would I put any other than a 2554 on a wall jack, unless it was an odd duck that fit right. Someone touches it wrong and its in the floor.
I want the lever back that used to be on wall phones that locked the phone down.

But that lever was from when phones were made to last forever! I also saw my share of 2554s with bent locking levers because new guys and novices forced them off the plate! Darn Newbies &^%&^

I just installed a 15 phone X16 system (+ cordless adapter) and needed to wall mount 5 of them. The spacing of the pins is not meant for a NA wall jack but is the same as a standard mud ring. However, the plastic is too thin on the mounting holes which creates a wobble. I used two of the studs furnished with the phones and Commscope (formerly AT&T, Avaya, Lucent, Systimax) M10L-262 wall plates which have a deep recess for a number card and screw. The metal collar on the stud fits perfectly in the screw recess and lets you set the stud to the perfect depth to hold the phone securely. I bought a pack of 10 wall plates for $12 on ebay (still listed). The jacks themselves can be found on ebay too or you can just crimp an RJ-11 on the cable. Using this wallplate makes for a professional installation and the phone is solid as a rock.

Food for thought....

I would never install a system that is even near to maximum capacity, let alone maxed out.

BruceR: I've mounted them to the mud ring, with pretty good success, might try your method if the need arises. It definitely is not a good design for wall mount.

For a business I wouldn't go over 75% but this is for my home and there won't be any expansion. We use the system mostly as an intercom and for the convenience of answering our doorbell and cell phones from anywhere in the house. I've had no issues with the system itself and am very pleased with it. I have 40 years in the phone biz and have retired so there's not a lot of phone traffic!