Catch,

I on occasion use drowners but most times I don't. That's why having to release them is no fun.

If I was tasked to catch only otters where beavers live, I'd avoid crossovers. I'd move downstream from the dam a fair piece and set in the narrowest spots available in the main channel.
Otters cover a lot of area, hopping from beaver pond to beaver pond. Beavers tend to stay in the big pond, especially in the winter months.

What Carl said ^^

You can catch otter in the smallest little trickle of water. They spend a lot more time on dry land than people give them credit for too.

If I was trapping trying to only catch otter and avoid beaver I would be setting narrow pinch points upstream and downstream of the beavers. I'd also be setting any little trickle that came into the pond or larger creek.

Also pay attention to tracks on the bank. Around here on larger creeks in sharp bends there will usually be sandbars. Lots of time on the back side of these sandbars there will be little pools of water where otters will hunt. You'll see their tracks getting out on the sandbars and hunting the back sides of them. You can catch them coming and going here with no fear of beaver.

Double up your wire or use cable and swivel a hip caught otter will shorten up a length of wire quickly in a coni.

If they are using the 6' creek, in 2 or 3 places, fence it off with sticks pushed into the bottom. Dig a channel with your foot in the center deep enough for a 330 and then brush it in and make it so they don't want to climb over the trap. I like to put a limb across like a dive pole. The deeper channel stops that too. You will catch them.

Firstly, thank you all much for your advice, I appreciate it! Secondly, I am set well for coon, ghogs, fox, mink, muskrat, but not for otter and or beaver. I do have some 330's and 220's but will pick up some more, including 280's, hopefully at the Ohio rondy.

As far as footholds would a 6.5" spread be ok or should I step up to a 7.5" like a Bridger #5? I don't want to get in to pricey traps for many reasons. Also, if not running drowners, to what extent do I stake these critters?

My vote would be bigger is better. I like the Bridger 5s. I always cross stake.

Listen to Beaverpeeler. I use mostly mb 750 on drowning rods but I’m not in beaver country maybe catch 12 a year

I catch and hold otters in 1 1/2 coils. An otters front foot and leg isn't much bigger than a red fox's leg. A 1 1/2 coil is plenty of trap. Anchor to a 24" rebar stake or wire to a heavy drag.

Years ago I caught a skunk in a mink snare. He sprayed all over so I hung him over a low limb to air out for a day. Next morning the snowy area around him was packed solid with otter tracks. That became my go-to otter set on big rivers. Hang a dead skunk or a crow doused in skunky smelling lure up on the bank and set foottraps on drowning wires in front. If there is an indent in the river bank then set a 280 or 330 between the indent and the attraction.
How good is this set? Had permission on a small spot (25 feet of riverbank) on the Delaware River in New York State. River was over 100 yards wide. Caught 11 otter in just over a week in this one set location.
I showed it to a good friend who flies under the radar (no internet mention of his name, no pictures, does not go to conventions, gatherings etc.) and makes his living catches huge amounts of fur, uses it extensively in several southern states on bigger rivers. He racks up over 600 otter a year (from all kinds of sets).

The live market otter people use 1.5 dukes