switerajaya,
The "rumor" you refer to was a speculation from someone that did not have their facts straight. There are many acrylics available in the market for a variety of uses. The "type" the person was referring to, is definitely a bad puppy. None of this style of acrylic is used in any product we manufacture and has never been use in any product we manufacture. On the MSDS sheet for BF Wet Diamond, it states there is an acrylic in it. The acrylic we use is a thickener and constitutes less than 1%, (which technically we do not have to mention on the MSDS because the amount is so small). It has no adverse effect and never has. Wet Diamond has been in use for 9 years, and has an excellent reputation.
You can apply it over the Karlack, but understand that the same issues exist concerning how ?clean? the surface is. If there is some contaminant on the surface, it may shorten the durability due to poor bonding. This would apply to any ?non-cleaning? sealant.
Concerning your application question, if you are using a polisher to apply, let the product ?haze? and then buff off. You may want to try a Gold pad as it will apply sealants more consistently than the red and very thin. We tell people if ?you can see the product going on, it is enough?. More is not better, put it on thin, let haze, buff off. If you want, you can apply a second coat. Give the first coat time to fully ?cure? which varies with the climate, but generally is good in few hours. If you are not sure, let it stand over night.
I hope this answers your question and helps you.
jk