I don't think it was that big of a boost. Garlic Jr. despite the power up was still considerably weaker than Piccolo who had the control of the fight pretty much the entire time except whenever Kami-Sama was being attacked by previous Guardians of the Earth.
As for Spice and Vinegar I don't really know what it did for them. The scaling for the Spice Boys seemed to be all over the place in the Makyo Star arc. Together all four of them can handle Piccolo (Spice was able to casually hold him back). Mustard and Salt were casually beating around Gohan and Krillin, yet Spice and Vinegar the supposed strongest of the group were beaten Gohan and Krillin. Hell Gohan can fight with Makyo Star Powered Spice and hold his own and fight with Spice and Vineger at the same time before killing them both (Via Rage).
I don't know where to put the Spice Boys and Garlic Jr. I normally put Super Garlic Jr. a bit above Namek Piccolo (Fused with Nail), while I put Piccolo around 3rd Form Frieza's level. Base Garlic Jr. I put considerably weaker than initial 2nd Form Frieza but still considerably stronger than 1st Form Frieza. As for the Spice Boys, I put all of them weaker than 1st Form Frieza or around his level, but Makyo Star Powered I put them stronger than 1st Form Frieza but still weaker than Base Garlic Jr.