Hi, thanks for your answer. :)
The reason why I wanted to include the non-stranded data from a specific tissue in the transcriptome assembly is that I am also interested in the gene expression within that particular tissue and these transcripts might be underrepresented when analysing the whole individual (just assuming). I'll definitely try to combine all the sequences and see how it goes.
Also, I already have 2 transcriptome assemblies - 1 from stranded and 1 from nonstranded data. So you are saying I can combine those 2 transcriptomes? how do I do that, do you maybe know? :)