G'day Simon,

The 250kg weight rating applies to the whole bed, assuming that the entire frame will have that weight somewhat distributed across it.
Generally, standard single stretchers have a weight rating of around 150kg, so each side should be able to support a significant amount.
As long as the whole 250kg isn't held on one side, you should be fine.

G'day Tanvir,

Stretchers are not commonly used with double swags, as there is a huge supporting bar down the centre.  
When using a swag on top you won't have as much support and you'll feel that centre ridge quite prominently, often causing people to roll to the outer edge in their sleep.
If you do want to use a stretcher you'll need one with the same dimensions as the footprint of your Dirty Dee 1400, in which case this particular stretcher meets those requirements.

G'day Gemma,

Yes, this combination should work, however, there will be some degree of overhang on either side as the mattress is wider than the stretcher. In general the Queen Stretchers are all around 140-145cm wide, and have a bar running down the centre, which may or may not suit the mattress you've got, as it will likely create a central hump running down the middle of the bed.

G'day Bec,

Yes you can pop a queen-sized self inflating or air mat on top of the Queen Kwik Cot Stretcher, however there is a bar down the centre, which might cause a bit of a ridge to form. This is going to be the same for all of double/queen width stretchers.

I don't have any experience with the Kings swags sorry, Lynette, but at a quick glance, it looks to be about 155cm wide which is 15cm wider than this stretcher. So it would fit on top with a bit of overhang which may be taken up with the sag in the stretcher anyway.

It's worth noting that there is a bar down the middle which people don't often think about when it comes to double stretchers.

G'day Chris,

Yes the Queen Kwik Cot Stretcher should suit your needs, the dusk to awn will be almost the exact width of the stretcher so it should work well. One thing to note is that there is a bar that runs down the centre of the stretcher, so if you're sleeping in the swag solo then you'll just have to sleep to one side.

G'day Mick,

The widest stretchers we've got are the Kamp-rite Queen Kwik Cot Stretcher (140cm wide) and the Oztrail Easy Fold Queen Stretcher (144cm wide), so they're close, but not quite 150cm sorry.