Any bullet that has a tangent ogive will likely be more forgiving and perhaps a bit easier to tune than bullets with hybrid or secant ogives. Although it's usually not too difficult to distinguish tangent and secant ogive bullets from a good side-view picture, hybrid bullets may be a bit more difficult. The transition from ogive to bearing surface in a tangent ogive bullet is very smooth and rounded, whereas a secant ogive bullet has a noticeable sharp or abrupt corner at the transition. Regardless, a call to the manufacturer should be able to clear up any questions as to the bullet ogive type, if necessary. Bullets in the 155 to 168 gr range are not necessarily "more forgiving" to tune. However, it's likely that a far larger number of rifles are equipped with barrel twist rates and throated for bullets of this length (weight), especially commercial production rifles.
That is why in addition to selecting the more forgiving tangent ogive bullet type, you will also need to know approximately how much free-bore the rifle has (i.e. how long is the rifle chamber throated?), as well as the barrel twist rate. The amount of free-bore dictates how much bullet bearing surface will be seated in the case neck when seated close to the lands, and the twist rate needs to be sufficient to stabilize whatever bullet weight (length) you select. Using those criteria, you ought to be able to choose a tangent ogive bullet that is appropriate for your rifle's twist rate and free-bore that should tune in readily. Without those two critical pieces of information, any specific bullet suggestions made here are not necessarily guaranteed to work well. If you have the twist rate and free-bore length numbers, posting them here might allow for more specific recommendations by other members of the forum. Alternatively, bullets such as the Berger 155.5 Fullbore, 175 OTM Tactical, 185 Juggernaut, and the SMK 155 (2156), 168 and 175, would be potentially good choices, as have already been mentioned.
