my standard set up is a
https://optechusa.com/utility-strap-sling.htmlOp/Tech USA utility sling plus a
Camera Hand Strap | Ultra Fit Hand Strap With Ultra Plate
the sling hangs cross body ( over my head and towards my hip ). it attaches to the upper attachment point with a quick release clip so it can be removed quickly
the hand grip attaches in two places, the upper attachment point, ( there is room for both on the same attachment point on my K 3 and K 5 II ) and the ultra plate attaches to the tripod point. It gives you an tripod attachment
*** the only down side is that the ultra plate attaches with an " Allen " (hex) wrench instead of a twist or coin screw head and it must be removed before you have access to the battery in the camera body
since I use the battery grip for the K 3 and K 5 II, that isn't usually a problem in the field because I can access the battery in the grip w/o moving the ultra plate. ***
using both at once, I have the option of helping with weight on the sling ( or excessive swinging ) by grabbing the hand strap.
due to the quick release clip on the sling, I can detach it if I want just the hand strap or I put the camera and lens on a tripod
I have used it with the HD Pentax-D FA 150-450mm F4.5-5.6 ED DC AW - 2325 g (82.0 oz.) w/ hood & tripod mount + HD Pentax-DA 1.4x AW AF Rear Converter- 126g (4.4 oz) - without fear of either the sling or hand strap failing
here
( 1) I don't have the rear converter mounted, just the HD Pentax-D FA 150-450mm F4.5-5.6 ED DC AW - 2325 g (82.0 oz.) w/ hood & tripod mount
(2) my thumb is under the hang grip strap [ the lens mounted is the HD Pentax-DA 16-85mm F3.5-5.6 ED DC WR [ Weight (w/o Hood) 488 g (16 oz) ]
(3) showing attachment point and sling's quick release clip