I've seen a lot of tongue jacks that bend where they mount in an A frame coupler from contacting the road [or kerb] because they don't lift high enough, and/or a bent tailgate from trying to lower it with the trailer still hitched.
Most Jockey wheels I buy need disassembling and greasing on the side pivot.
I buy the type that locks the wheel so it doesn't flop around and slowly unwind when fully up [this can be a DIY mod with a roll-pin]
Larger wheels will always roll nicer on paving stones etc, but I've found that a wheel larger tha 8" lifts the jockey wheel so it is difficult to fold away when hitched to a low vehicle like a S/W of Falcon/Commodore Ute.
If you mount it further back [like in my photo] you generally can't use "C" channel in the tongue construction because of poor torsional strength of "C" channel
I mount mine inboard for aesthetics [and a bit more Jack-knife prevention]
You can DIY make a decent Jockey wheel yourself by use a H/Duty corner stabilizer/jack from a caravan [travel trailer] and attaching a decent industrial caster wheel to the leg.
you cut the leg horizontally at the desired height ,then weld a plate with 4 holes to it [eg: where I've marked it]

Then bolt an industrial caster wheel to it.
These ^^^ are both rated at 2000lbs each . And you could wind it up ,so it tucks out of the way.
A good project for a GJer