Don't buy things you don't need. You can lower that tank by cutting into that bulkhead. Most of my fleet is inverted and a couple P-51's also. Just be creative and rebuild that bulkead area. Its not that big a deal. I have done this and my inverted engines run just fine with no Cline

Just need to watch out how low you go or you won't be able to get the wing in. Clines are great. I have them but you don't need it and it is just one more problem when it comes time to look for problems