Im not sure what is the best strategy to get "similar images" approved.

When you have same image with different editing, or different angle, pose... you can send them together in the same batch or you can upload in different batches.

Are there any differences or you get the same result?

My experience is that if uploaded in the same batch, not all of them are approved...

123rf usually reject me "similar images" when they are in the same batch.
SS...

123rf is the pickest with respect to similars - sometimes making really crazy choices, IMHO. However I don't think it's worth playing games with batches to try and get them approved.

The sites make their choices and it's very rare they all make the same one for those that do restrict similars. I can only remember one or two occasions when SS rejected a similar.

The only time I restrict uploads are to iStock where it's a composite or raster illustration I'm sure they won't accept - something I did with SS and others in mind in the first place.

123rf is the pickest with respect to similars - sometimes making really crazy choices, IMHO. However I don't think it's worth playing games with batches to try and get them approved.

Once again I agree with you JoAnn.  Too much trouble to pick and choose batches with the goal of getting the maximum amount of similars accepted.  Let them take what they want. 

The only time rejections for "similars" really bothers me is when some rogue reviewer  (like the recent one at SS) rejects ALL the similar ones for being similar.  Lets face it, the only way they are "similar" is if you accept SOME of them