Are you actually getting mana screwed, or are you just ending up with the wrong mana? This is why I never use more than two colors in a deck.
But yeah, that looks light on land to me. Even with Birds of Paradise in the mix, because they depend on getting lucky with forests. I'd aim for at least 18 land cards in a tricolor deck of 60. Maybe even 20.
It seems to be a combination of the wrong color and not getting mana at all. The deck can run on one each of the duals, but sisters, cats, and strength are the only ones that require multiple specific mana. I'd rather run
Incinerate over
Giant Strength, but it wasn't printed prior to 1995. I have a set of
Blood Lust, but they're 4th edition, and some 93/94 groups don't allow 4th edition, even though it has the same art/frame.
Yesterday, I ended up replacing
Onulet and COB with a
Mountain,
Island, and
Forest, and it seemed to run better. I could achieve the same, and even shift the turn clock back one if I do three Moxen instead, but I want to keep the deck at $5000 - adding three of the power nine would more than double the current deck value. I did a vintage tournament a few months ago, and ran 1-land belcher:
I took third...
Force of Will wrecked my day. Losing
Gitaxian Probe to the B&R list really made me blind when triggering mana production.