wiring 2 speed efan w/ controller

I searched and found some good threads but they were closed and none answered this specifically. I have a Taurus 2 speed fan that I am putting in a 1990 gmc pickup. I have a Hayden 3647 fan controller with temp probe in radiator. My ultimate goal is to have one speed of fan run with temp probe and the second speed run with A/C. Both the controller and the A/C are + switched. I think I can run the low speed through the controller because it has a 40 amp relay built in and low only pulls ~20 amps (running). To run the high speed though I will need to wire 2-40's together to handle the ~35 amperage (running). If someone can help me with this, using standard 40 amp relays (spdt) and the controller I already own, that would be fantastic! Thank you.

Here's a link to the controller I have. Hayden 3647

I found this diagram that looks like it would work but I need an additional relay on the high speed side.

also, maybe like ckeeler suggests here: https://www.the12volt.com/installbay/forum_posts.asp~TID~107972~KW~fan~PN~0~TPN~1 I just don't know if the temp switches he references are + or - switched.

Use a properly rated relay - using 2 in parallel leads to premature failure (different closing times) and if one fails, the other burns out. (I use a 60A changeover relay for my battery isolator.)

I fully intend to use a proper one but, I have to order it. Right now I just want to 'get by'

https://www.the12volt.com/installbay/forum_posts.asp~TID~98402~PN~2~get~last

I've seen relatively cheap continuous rated relays of 100A to 250A for ~$20-$25 stateside. But may as well order a 60A or 140A etc (which are almost "regular" relay size).