Hello Jack and welcome.
Nice choice regarding collecting shillings. They were my favourite denomination when I had a schoolboy-style collection about 40 years ago, and the first place I resumed when I rekindled my interest back in 2014.
I too have a type set of shillings, of variable grade and quality, going back to Charles II. I don't have one of absolutely every type (you will need patience and deep pockets if, for example, you want to have things like the Welsh Copper Company shillings of the 1720s) but I have at least one circulating shilling of each monarch, and usually each different bust of each monarch (certainly since George II). This type set contains 40 coins in total and stretches from 1676 to 1959 (Scottish).
Some of these coins are GEF or better but most of them are significantly lower grade - they range from NF (a 1905 shilling) upwards but I would buy almost all of them again and have no strong desire to upgrade them.
Since rekindling my interest I have bought a little bit of everything, from the quarter farthing to the crown. Half crowns and florins are probably my favourite denominations but my first love was the shilling. These days I'm not buying predecimal, my coin collecting bug has taken me in a different direction - but I still get the predecimal collection out from time to time, admire them, remember where they came from, and enjoy being their custodian.
Enjoy your journey!