Basically I need some help choosing a general bikepacking tyre for my new bike. I am as yet undecided between the Continental Mountain King, X-King and Race King. A few factors to consider:

They will be used on a rigid 29er for general bikepacking use, which places rolling resistance as an important factor. I currently have the Mountain Kings on a general use 26er Hardtail, and they are ideal general trail use. However, am I correct in thinking that to get the 'equivalent' amount of grip on a 29er then the tread need not be quite as aggressive, due to a larger contact area? So perhaps an X-King would give the 'same' amount of grip as the 26er while having a lower rolling resistance? Do any use Race Kings? Do they have enough grip for all year bikepacking use?

In addition to this, would 2.2 or 2.4 be more appropriate? As it is rigid, would the larger one give a slightly better ride? Is this a good trade off for the extra weight and rolling resistance?

Finally, just to muddy the water further.. Are there any other tyres that would be worth considering? Any Schwalbe or Maxxis?

Any help would be appreciated. I realise that's a lot of questions..

I use 2.2 Race kings all year round (unless it's snow or ice). Never really had any issues, opinions about them do tend to differ quite a lot though ... I'm a firm believer that grip as as much to do with technique as it is tyres

For low rolling resistance they're pretty hard to beat. If you feel that you want something a bit 'grippier' how about RK on the back and XK on the front ? Should be a good combo.

Maxxis Aspen rear / Ikon front would be one to consider too.

Good balance of grip/weight/rolling resistance.