Hi and welcome , I would say the HEQ5 will be easily up to the job of holding the 8 inch it would work great for visual and limited AP if you go that way .
As the Newtonion has the eyepiece at the top you can use the mount with the legs under 1/2 way extended improving stability a lot .
Here is my HEQ5 under my C9.25 and it holds this OTA easily and the 8 inch OTA is a lot lighter than my CAT which is quite a substantial weight , compact but solid , very good for visual and I don't do AP except a few moon shots .
I would buy this mount and put the saved $$$ 's into a few nice GSO Superviews a Telrad and red torch etc .
Brian.