Here is my opinion: They will get you through initial aceptance, maybe to EIB, but I am pretty confident that you will not get CEN certification with these, because overall they are not that accurate, and CEN is all about being accurate .
I have said it on many an occasion: I suggest that one pays the extra buck/dollar/pound to get a pair of proper boots, that will last you a lifetime, are good to walk in (you spend quite a lot of hours on your feet while trooping), and are very accuarte at the same time (I have made a thread about it).
A lot of people are hung up on TKBoots, and I am not trying to talk bad about them, but they are really not that accurate IMO. White leather and white elasticband instead of dyed white, plastic soles instead of leather...I would choose Loakes 290 or similar any day.
You can use either acetone or painthinner, but like I told you in the PM, I advise not to scub, sand or anything like that, as it will kill the leather.