It seems like a bit of a leap to go directly from brown to 150g. Try clears first, if you really want something heavy. Grays are about the same as clears anyways. Check out some zealios if clears don't work out since they make a nice middle ground between default browns and default clears (I'd argue 62g is better than either but that's my opinion). After having gone for 45g topre boards I find that my ergo clears feel lighter then they used to, but I still don't think I'd go straight for stock clears either, maybe 65/67g zealios if I go for another MX board.