When I do work ups I shoot what ever it takes to get from the bottom to 80% of the load window. Usually in 3 shot steps . When I have a idea of where to look in a load window then I work it in with 5 loaded 3 on target and 2 more to verify a good load . I've had several rifles that will shoot 3 then toss the last 2 out .
I did shoot some 10 shot strings this weekend ,the answers at the end , for hunting grade guns at my level of skills round count means zip if the load is good . My shooting degrades as I get deeper into the recoil therapy. It's only fair the 2nd day . I shot 6 rifles and almost 200 rd at ranges of 70,94 and 260 yd in loads from mild cast to moderate jacketed to rattle your caps .
My last group this morning was 10 rd at @94 yd the 2" dead of winter load was 2x4 and 10" high . Same rifle and load at 260 1st string put 3 of 10 in solid impact on an 8" gong.
I think that yes longer strings will show up more abortions but most of the abortions can be mechanically eliminated . Crimp,cases,bullets, seating, sizing etc . All that leaves is powder,primer,bbl, sights ,and machine work . Out side of that lies induced abortions ,now a lead sled and external trigger device can fix those ,but then you could just machine a bbl and locking breach in a 200# slab of steel square stock anchored to 1000# granite. Consistent but not terribly portable and it should remove all human error .