Is there anything actually incompatible with "MS-DOS" 7.10? Besides IO.SYS needing a patch to run Windows 3.11, I've never had any trouble with it. I usually stick to DOS 6.22 on 3.11 builds, though, for authenticity, but it is a bit easier to get ridiculous amounts of free conventional memory on 7.10 thanks to it supporting moving a bunch of stuff to UMBs (STACKS, FILES, etc.)
MS-DOS 6.22 can do the similar if not same. I never had anything less than 615-620 KB even with all the drivers and such (ZIP, SCSI, Stacker, etc.), and never faced with any application requiring more, even during the times. It's support for FAT32 might be considered as an advantage, but I never did any DOS rigs having more than 2GB partitions, anyway.
I suggest sticking with 6.22, myself. I like 7.1, its indispensable in a boot floppy for repair/recovery/maintenance purposes, but at the and, it's a hack from Windows 98 distributions, whereas 6.22 is a real standalone OS.
GA-6VTXE PIII 1.4+512MB
Geforce4 Ti 4200 64MB
Diamond Monster 3D 12MB SLI
SB AWE64 PNP+32MB
120GB IDE Samsung/80GB IDE Seagate/146GB SCSI Compaq/73GB SCSI IBM
MSDOS 6.22+Win 3.11/95 OSR2.1/98SE/ME/2000