Is it possible to use documentclass like wileySix as book template in rmarkdown?

Question

I would like to use a different template than the default defined for documentclass: book such as the wileySix. Would that be possible? Maybe by including in_header: file.tex and inside such file I could define \documentclass{wileySix}?

Then basically I have here two question:

1. Would a pdf document created from R Markdown be compatible with different documentclass for books?

2. and if the answer is "yes, by declaring the \documentclass inside a file.tex and calling/including it by your YAML", as I have never used the file.tex, how would I could do that? any help is very welcome