Call/email Kevin Deal, he will give you solid answers. The plate voltage concern is an easy one, get the specs and see; personally, I think that in your cases you are worrying too much about that one issue.
http://6streetbridge.blogspot.com/2014/02/tube-review-reflektor-6p3s-e-power.html
http://6streetbridge.blogspot.com/2014/02/tube-review-reflektor-6p3s-e-power.html