helm-git-grep and helm-swoop at the same time

Question

I heavily rely on helm-git-grep to find stuff.
When there are just too many results though, I'd like to narrow the results down with file name. (possibly with helm-swoop)

Here's what I do for the above situation.

1. I run helm-git-grep then,
   save it to wgrep buffer using helm-get-grep-run-save-buffer,
   isearch or helm-swoop on this buffer to narrow down.

2. helm-git-grep and find too many results. quit helm-git-grep and run helm-browse-project to filter on files first,
   then run helm-ls-git-run-grep on filtered files to narrow down.

I feel these two options are subpar and wonder if there's a better way.

If I do helm-git-grep then try to run helm-swoop I get helm: Error: Trying to run helm within a running helm session error.