I don't have issues with this fight.... Especially with Phase 2. I use Marron > Synchro > Rappy rotations. Killing the nodes is easy with Rappy Stomp, Generic Synchro Combo, and I've had lv3 Marron 1-shot PD's parts.
If anything, Summoner have it easier with Dia Master, I never have to worry about my HP. I only top off to trigger bonus dmg from Perfectionist (R).
Are your pets at least 13* and have sweets in their box? I would like to share more insight on how to make this fight easier... I'm usually one of the first few done in my alliance for solo PD.
Better off comparing each other's complete builds including buffs and passives that come into play while fighting.