Ultralight to me is a 6-6.5lbs sheep rifle which I assume is what your looking build if you want to shoot the 145 lrx.
I used a Borden action,McM edge stock and a #2 contour benchmark barrel @25”,that landed at 6.5 lbs bare including brake and scope rings
I was hesitant when I bought my action after what I had read,but I must be a lucky one because it runs perfectly,smooth easy bolt lift,mine is nitrided.The axiom looks good,but a straight bolt handle on a 60* action,meh no thanks.
I have that exact scope and I really like it,I don’t find the eye box a problem it just requires good head position at higher magnification,I think you will be happy,mine is on a LR hunting rifle.
Benro LBA2 works well and rated at 110 lbs,my only dislike is the adjustment lever,I would much prefer a screw knob type but I can live with it.I also have a RRS BH40 and can say the LBA2 handles vibration better.
Gotta agree the MF and bighorn are a little sloppy for my liking,I’m about to pull the trigger on a Curtis or another tempest,I just love the short bolt throw!