Thinking of doing the same...

Yes it was. The 10x10"

I went with Bennett because I preferred the stainless steal and they offered a lifetime guarantee while the other (Nautico I think) offered 1year

What brand did you buy. Was it a Bennett?     

2 different beasts.

I had one on my boat until I was told they create too much drag which is why I removed it.

This download provides some very good info on SLT's

https://nauticusinc.com/wp-content/uploads/2020/06/nauticus_improving_small_boat_performance.pdf.

I didn't buy this brand, but as said the information was/is very good

I was a bit wary of that first time out, but there were no issues. You ought not to be able to go fast enough in reverse for the tabs to cause problems

In any case both tabs would be deployed down with equal pressure on both sides.

Just as a side issue. I contacted the manufacturer of those that I bought and asked about operating in a following sea. He told me to raise the bow using the engine trim to stop it from digging in and broaching.

I have since read the same thing from another maker.

Oh. Just read my original question again.

Unsure about the drag but I don't think so.

A big yes to the tranny.

Major interference while at speed but nothing in the 5-8kts region.

Personally I am not bothered. I do have room to move tranny further in towards the center but as never look at sonar screen when going to/from proposed fishing area, I doubt if will bother.   

I thought it about time to write my own reply.

In short, the fitting of these SLT's has been 100% successful for what I hoped to achieve.

I had two issues that under certain conditions caused me grief.

The first was falling off the plane when it was necessary to slow down butting into head seas.

Because the SLT's allow you to remain on plane at slower speeds, this problem no longer exists (when operating in the type of weather/sea you are normally comfortable with).

Second issue was with the wind coming from beam through to around 20 degrees off the bow, the boat would lean (sometimes uncomfortably so) into the wind as I steered against this force in an effort to hold course. The stronger the wind, the more effort needed to hold course and the greater the tilt into the wind.

Again, because the SLT's act independently from each other, the tab on the lee-side deploys and levels the boat.

I did notice a third plus and that was I can now speed over lumpy (judder bar) sea without the accompanying jarring which makes the ride so much more comfortable

and I don't really know why this happens!

So that's my experience with these additions so far. There maybe some negative/s I have yet to find out. Have to wait and see.

One last thing. Contrary to the advertising of these fitments, I have seen no decrease in fuel use!    

Anyone out there have any experience with this (SLT) devise.

In particular: Do they work? Do they cause unnecessary drag?

Do they interfere with a transducer?

Any comments welcome.

Cheers