Do you think they were made for these companies by Susato?
Are these new or used whistles that you got?
How do they play and sound?
And do you have the Susato in C black plastic to compare them to?
....arrived today, first impressions, they seem to play well, with a fairly easy second octave.
On closer inspection, they do seem to be the same whistle(!), exactly identical, (to me), except for the printed name on them, & the supplied cases, (of which the Recorder Workshop one is better).
So if you're looking for a plastic whistle in 'C', I'd suggest trying the Recorder Workshop one. 
.......found a couple of plastic whistles in 'C' on Ebay the other day.
One is a Glenluce, (which got a pretty good recommendation from a suggested video on Chiff & Fipple), £14.95.
The other is by Recorder Workshop, £5.50.
(They both look like Susato whistles do.)
Surprised you think it weaker sounding than tenor recorder, my Yamaha was really a soft player, to my ear, but I find my Howard low D has what I call a 'fuller sound'/ 'stronger tone'.
I quite liked the tone of yours when I listened to it being played online, but decided on the Howard 'B' stock as it was cheaper, & not knowing how I'd get on with a low D finger stretch, (I sometimes still don't quite cover the holes, & get that odd sound, when you don't).
Try this:
https://www.youtube.com/watch?v=vDqI46zfUV8&list=PL9CRnS8InnK4TaaDA0biS1dfnrAzH7yP9
Tone wise, I think it's pretty good, it has quite a strong sound, if I get it right, (but I can't really play it yet, I need to find my embouchure on it).
Depending on the music, & how I feel, I'll add staccato, &/or slurs, just to make it mine, (sometimes even vibrato) - I think we need to interpret some tunes our own way.
OK, here's a first attempt with it.
It's got a lovely tone in F, Keith! Very pleasant to listen to. :)
Here's a challenge for you- at certain measures to go from one note to another without tongueing. Like from note 1 to 2, OR from note 3 to 4 in a measure.
I catch myself with both tongueing and bowing I tend to always do a new tongue or a new bowstroke with every note. It always sounds better when I slur some note transitions on the same breath or the same bowstroke. Mind you, I'm a rank amateur but I've found that it sounds good when I vary it -once I am able to. :D
OK, here's a first attempt with it.
https://soundcloud.com/user-604445267/zoom0003/s-Su14o
(Still got to work out where to set the embouchure hole in relation to the finger holes.)
We had about 9 inches. (such an appropriate subject for the 'drifting thread' lolol)
It's not as bad here in NY as in Chicago, but it's been pretty darn cold too- this morning at 10am it's minus 1 degree F. Brrr
No, it's not easy finding your embouchure on a flute, but it will come - & then it's just a matter of perfecting it.
All I can offer is that you place it's front edge on the bottom of your lip & go from there, by rolling it in or out, until you find where it works for you, everybody is different, & it will take a bit of time, good luck.
Well, here I am buying a couple more whistles, & I expect you're all thinking that I'm being extravagant, but honestly, I went through life without the means to buy & try stuff, & am now only just able to, so I guess that I'm just making the most of what time I have left - I'm not getting any younger you know. 
Lovely mellow tone on that whistle, Larry.
I hope both of you love your new low whistles!
Ah! The waiting..........hope you don't have to wait long.
(I was quite surprised when mine turned up unannounced, but pleased.)
Re small hands - it might be worth you taking a look at the 'Tutorial (Low D)' that I posted a link to, she has small hands.
Exciting, you guys!
Wish I had bigger hands... At least for now, I can't play anything lower than a G at most. 
Wow, sounds great! But it's huge! 
Larry is that an aluminum whistle?
As I have reported in another thread, thanks to a post on another forum, (you know the one), I have put my money down for a Howard Low D - so the New Year will be time to knuckle down & learn to play my low whistles, & my Low D flute, & that sounds like it will be a Happy New Year, for me at least, can't vouch for my neighbours. 
Good one Keith.
I'm thinking it may be an old one, maybe of original manufacture, as it is a bit beaten up looking, & may have been repaired down the seam at some time. But it's got a decent mellow tone to it, so not a disappointment at all.
The other two are as other people say about them, soft easy players, (somewhat like my Tony Dixon ABS), & likely to become one of my favourites for practicing at home on, (won't annoy the neighbours).
Which one is the silver one?
OK then I'll try adding photos here.......seemed to work.... one of all 3, the other of the flush fipple whistle, with the rough seam & head removed. (Black is not the easiest of colours to photograph, unfortunately, but the fipple head has 3 ridges to hold it in the tube.)
Keith, if the photo file isn't too giant, you should be able to embed or attach it to your post in this discussion, too.
See one of the top discussions, on adding images to a post here:
https://pennywhistleclub.com/forums/forum/site-questions-how-do-i
Low D improv
