Going from 10w-15w fork oil with progressive springs

[afatrat 18]

First post so, Hi, and let me say you guys seem to have a great community here. Hopefully I'll be able to contribute where I can.
 
I recently installed some Hyperpro progressive springs in the forks but used Belray High Performance 10w oil which is about the same viscosity as stock (33 cSt). I didn't use the Hyperpro 15w that came with the springs as it's winter here and figured I'd try a lighter weight. Also, it seems that Hyperpro may be rebranded Putoline 15w which is 67.5 cSt. Seems like a big jump.
 
Now that I've gotten some time with the setup, it seems when the forks compress over bumps and ridges, it is much smoother. However, when the forks need to extend for dips and drops, it's still really harsh. So my question is, would going to the 15w help? It seems like a heavier weight, and specifically that much heavier weight, it would just reverse the situation (harsh over compression, planted when extending). It's also hard for me to tell what exactly I'm feeling as the rear shock is a pile of garbage regardless so I'll definitely be replacing that.
 
I put progressive springs and the same Bel Ray 10w in my 2000 gs500 with a stock rear and that thing is miles ahead of the 07. Pretty disappointing to have the lowly gs smoother and better planted than the 07.
 
Any input is welcome and appreciated.