having a portable bench made for P.dog hunting. What length legs should I have cut?

1. 5 gallon swivel bucket or
2, Drum stool

7 gallon bucket

I just made one using the leg brackets from Lonny. He recommended legs cut to 32”. That works great for me sitting on a 5 gallon bucket.

Thank you sir

I made this one at about 34.5" tall. A mechanics adjustable rolling stool works great and has a better cushion than a 5 gallon bucket..

The taller you can sit would be more comfortable for your back and legs. You may be able to find a 6gal. bucket somewhere. A little taller than a 5gal.
https://www.ssisports.net/Products/421071

https://affordablebuckets.com/product-category/6-gallon-plastics-buckets-with-wire-bale-handle/

Or if you want to get fancy this looks like a nice setup.
https://www.peregrinefieldgear.com/new-peregrine-field-gear-venture-bucketpack-SGB.aspx

Also used Lonny brackets and the suggested 32”… I use a metal folding chair with a cushion/towel and it’s the right height for me

I have a drum throne, works fantastic, up hill, down hill, flat ground.

1.25" diameter legs cut to 31" & threaded on both ends...caps on bottom

20 Vartarg on table

Buzzaw: Both of my "swivel" type (which I highly recommend!) Colony Varmint commercial shooting benches have built in/on seats and the distance from the seat to the bench top is a pleasing 19" and 20" respectively.
My homemade non-swiveling Colony Varmint shooting bench has pre-made (commercially available at hardware stores) iron pipe legs that are 31" long including iron end caps.
I carry along a modest weight but very sturdy folding chair to sit on for use with my very sturdy but non-swiveling home made shooting bench.
If I might interject a suggestion here - that would be to go with either a commercial or a home made ( I have both!) swiveling/rotating shooting bench with built in seat.
These are so much more useful and efficient afield.
I love my fixed leg shooting bench that I made "extra-sturdy" about 35 years ago, and used exclusively for 25 years. But my homemade and my commercial swiveling/rotating shooting benches add much fun and less effort afield.
Best of luck to you in your project.
Hold into the wind
VarmintGuy