Congrats on your new Enfield!
I've always said that if I had to pick a bolt action rifle to take into combat, it would be the No.4 Mk.I, hands down.
Length of pull can vary, since there were different length buttstocks made for them.
Since good surplus ammo is getting scarce, I reload almost everything for mine, nowadays. Prvi ammo isn't too bad, but their brass is tops for this caliber, IMO. There are three bullets that I prefer and some of mine show a preference for one over the other. They are; Hornady .312" 174gr BTHP, Sierra .311" 174gr Match King and the Sierra .311" 180gr soft point. I usually use Varget or IMR 4064 for powder.
While I like the micrometer sights, I've also become accustomed to the L type flip sight and have no problem using it, so long as my loads match the service load/calibration fairly close, but it may depend on the type of shooting you do, too.