You have to be careful with this advice because Vaporeon vs Golem is a far bit more complicated.
Look at the Graph on countering Legendary Dogs page https://pokemongo.gamepress.gg/sites/default/files/inline-images/image3.png
Vaperon is just over 16 DPS
Golem is almost 17. (and don't forget Dragonite) so yes Golem is about 7% more dps.
So if the TIMER is your issue: then replace Vaperons with Golems helps.
But Vaperon actually does more damage per vaperon than Golem does. So if your phone crashes when you try to rejoin or takes significant amount of time to rejoin, Vaperon will outperform Golem.
The other thing to take into account is Levels. If your players were 33+ before the Gym system switch there is a good chance that they have 35+ Vaperons vs only 30 Golems.
Another thing to consider when planning out a small squad if the Auto-selector HATES vaperon and LOVES Golem. So if you know you are going back in, start with your vaperons and let the autoselector pick Golem on rego.
Last Saturday I had a friends phone because he had to work on Fridays Mew2 raid and I didn't. I also have my kids devices and decided to try to "Solo" Entei with 5 Devices. Accts were 39 37 35 35 35. Went with 6 Vaperons in first phase and golems came out in second winning with 24 seconds.
Losing 8-9 pokemon in total.