Does using god ki in base form makes you stronger than turning into super saiyan?
It was stated during the fight between Beerus and Goku that Goku had absorbed god ki into his base form which had indeed made him significantly stronger. Gohan, on the other hand, hadn't trained and his base form at the time was nowhere close to even teen Gohan who fought Cell. So his SSJ multiplier to his base form would've been very low. Freiza's first form was most likely stronger than Namek saga SSJ Goku. However, Goku has gotten substantially stronger since than and he was completely dominating the fight against final form Freiza who had gotten a lot stronger. 

The Golden Freiza multiplier is a lot higher than the Super Saiyan Blue multiplier. This is why Golden Freiza was a lot stronger than Super Saiyan Blue Goku despite Goku's base form being a lot stronger than Freiza.