I've been through this before myself. When I did my first swivel ball replacement (20yrs ago..), I set the preload on the swivel balls way too tight (not enough shims on the upper pin). I think the manual says something like 12-16 lbs. But I had probably 25. Anyway, the effect was that I was always having to re-correct when driving (particularly noticeable on the interstate), because there was too much friction for the wheel to "self-center" like it is supposed to.
Long story short, you should definitely be able to turn the wheels by hand without the relay hooked up. If the swivels are good, the relay will not create enough resistance to matter.
I also rebuilt my steering box thinking that was another possible issue, but it wasn't.
61 II 109" Pickup (Restomod, 350 small block, TR4050)
66 IIA 88" Station Wagon (sold)
66 IIA 109" Pickup (Restomod, 5MGE, R380)
67 IIA 109" NADA Wagon (sold)
88, 2.5TD 110 RHD non-hicap pickup
-I used to know everything there was to know about Land Rovers; then I joined the RN Bulletin Board.