Is the album with mons you got still up to date? There's most likely something better than Wargreymon you can use as leader. While his skillset does look good at first sight, he's simply too slow for PVP.
That team should probably work on lower tiers, but in the long run you want a healer and brown card generator. For healer you can make Cerberumon Werewolfmode or Ceresmon Medium, both at their respective Aegiomon Trial island.
Cerberu is easier to make and he's unresisted, but in the usual Larva team you want for high tiers it'll be harder to rune both properly due to same color.
As brown card generator you can use Chaosmon from Flash Tickets (keep all your Batteries for Flash Events, there's one each month to my knowledge) until you can finish Holyangemon, also from Flash Tickets.
That would leave you with three more open spots. Ofanimon is great for the direct damage each turn, Highandromon is ok until Gold 2, after that he's a bit slow. You could also use the God+ Dorugamon or Death-X-Dorugamon for another 1 turn damager here, but that's up to you.
Last spot should be a tank, Craniummon does work great (used him myself all the way until hitting Legend for the first time), best choice in the long run would most likely be Ancientgreymon or Blitzmon as they also give you a +9 skill.
That team should reliably get you to Gold 2/1 even without Larva, and allows you to farm a weekly Burst Cap, God+ rune aswell as a good amount of GSP tickets and gold disks.
About runes, don't bother while your PVP team isn't really worked out yet, or you will end up like me and have to switch them around all the time, which either gets expensive or takes lots of time to get free hammers. Try to get 5x God+ runes of each type, if your PVP team isn't ready by that time you can also start making SP runes and then rune any more or less permanent members in your PVP team.
Try the 45e island for Cranium, if you still struggle to get any drop you can also evolve him from Knightmon, that's one more evo step to SP but better than nothing.