What is Reddit's opinion of ZOECON 619907 Gentrol IGR Concentrate Insect Growth Regulator, 16 oz?

From 3.5 billion Reddit comments

Look into insect growth regulator! A couple of years back, I had accidentally brought in some German roaches from my previous apartment back to my parents house - we fought tooth and nail to get rid of them! We used this stuff but in a smaller brown bottle and diluted it as instructed, and sprayed the crap out of walls, near our problem areas every two weeks (we went hard on the problem and even just straight doused it without dilution at one point, because why not? ) and guess what? Their wings were forming in deformed, and No more roaches after about two months! No more fruit flies/sink flys either! They looked like they had egg sacks even, but then they just never hatched!

Here’s a link to the brand we used

ZOECON 619907 Gentrol IGR Concentrate Insect Growth Regulator, 16 oz https://www.amazon.com/dp/B003Y663JE/ref=cm_sw_r_cp_api_glt_fabc_EAN8JE59G1QSP9QH6GQ1

Do you mind if I ask one last question. (Please no pressure, and no pressure to answer quickly.)

Do you know how much gentrol I should shoot for purchasing, to mix in with my Alpine WSG? They have these 16 oz bottles but they are very costly. (The instructions on it say to mix with 1 gallon of water, but I wasn't sure if you would use less if mixing it in with the alpine). As a cheaper alternative to Gentrol, could I mix Tekko Pro - which is also an IGR into the Alpine WSG instead? (It seems to be about half the cost for 16 oz). The Gentrol liquid sure has stellar reviews; if you think it's worth the additional cost, I will surely go for it.

Sorry, would have asked earlier but i only got to this now. No pressure..

Okay so I'm pretty sure it is what I feared cuz I also posted this in r/insects. But my problem is that I live in Canada, and getting Alpine and Gentrol is about a total of almost $500. I'm looking at this Alpine and this Gentrol. Is there anything more cost friendly in Canada?