Apex Tool Lab tools are an excellent alternative to consider.

Many thanks, LarrySabo for showing this link.
while I am a newbie (actually no experience in head replacement at all tbh), what should I acquire first? the ramp version or the e-type (unstick)?

I think you will get more immediate use out of the Ramp tools.

I've used Apex Tools and thought they were good quality and not too expensive..

while I am a newbie (actually no experience in head replacement at all tbh), what should I acquire first? the ramp version or the e-type (unstick)?

Given your admitted lack of experience, I would suggest doing head swaps on drives you own until you can do so successfully every time. Only then do head swaps on customer-owned drives.

To track how you are progressing, take one of your sacrificial drives and do a Read/Verify scan with HDDScan or Victoria and take a screenshot of the results. Next, remove the heads as if you are going to swap them to another drive, then re-install them into the original drive and repeat the scan. Take a screenshot and compare before and after results. You should end up with something like the image below.

Do this a number of times with various drives until you feel comfortable doing swaps and results are consistently better or not much worse after the swaps. Then you are ready to do swaps on customer-owned drives of the same models. When you encounter a new model, practice on sacrificial donors of that model before working on the patient.

It's much harder than you think. I never undertake it myself after much practice and many failures (thankfully on old drives). Because data recovery is only a part of my business I outsource physical damage to a specialist DR business and do the software ones myself using HDDSuperClone Pro, DMDE and sometimes MRT Ultra.
Just remember what I was told on a DR course a few years back, never open the drive unless you have to as the chance of losing everything will be greatly increased.

The other thing to bear in mind is sourcing donor drives. There are specialist companies around and eBay is always an option but you really need a good supply of all types of drives if you want to turn jobs around quickly.