Am I correct to say that the end needs to be 1/8th BSP?
My gun has a solid pipe, I read a hose would be better?
Also is a push on or needle nose coupler be better?
Then I need to buy wheel bearing grease for everything.

 

Yes, a flexible and a push-on coupler is essential; the pic of the coupler and flexible above is what you need. This grips the nipple so that the grease actually enters the bearings/UJs.

 

That spring-loaded trigger-action coupler is nice. The other style works, as long as it doesn’t get slippery and un-grip-able.

 

Has anyone used Inox MX8 marine grease?
I am thinking this would be suitable for wheel bearings.
1 x gun / grease for everything.

Any advice on washing and repacking wheel bearings – front and rear?
Inox MX8 Marine Grease Cartridge
UPC: 35920

DESCRIPTION
A premium industrial grade, extreme pressure, high temperature lithium complex PTFE grease suitable for a wide range of applications.
Lithium complex grease, which means that it will hold together extremely well under high pressure and variable temperatures
Excellent resistance to water and water wash out even at elevated temperatures
Suitable for marine, automotive, aviation, bearings, commercial, earthmoving, electrical, farming, fishing, industrial applications

450gram cartridge
$27 NZD for a cartride

https://www.burnsco.co.nz/shop/boati...ease-cartridge

 

Any decent grease will be fine.