With you having a brand new pool you don't need the XL option but it will not hurt anything to have it. You will not run out regents that is for sure! You do want everything else for sure!
Manual vacuum-a simple vacuum head like this:
Swimline Hydrotools 8130 Swimming Pool Butterfly Weighted Vacuum Head Cleaner - Walmart.com and a hose long enough to reach to each end of the pool and across. You will also need a skimmer plate like this:
Amazon.com : HydroTools by Swimline Oly Replacement Elbow & Plate Low Profile Skimmer Vac Adaptor, White : Swimming Pool Skimmers : Gateway BUT make sure to try to get it local so you can measure it to make sure it fits your skimmer. Lowes, Home Depot, and pool stores should have them.
It will take some learning to figure out how to get it primed and working but once you do it will work good for quick clean ups and such.
For everyday cleaning NOTHING beats a good robot though!!
Kim