Something seems off here. Although the information is appreciated, how did you come to have this knowledge if you have just returned to cards after a good 25 years off from collecting?
Apparently you are an artist. Are you in any way affiliated with these Miller/Monarch cards either as a designer, printer or seller? if not, how do you know this seemingly insider information you shared?
https://www.net54baseball.com/showth...70#post2038470
I did not mean to diminish them, by calling them handmade. What I meant by that is that they seem to be printed by someone unknown other than the name Miller Press, but not licensed, authorized or widely available until they started showing up on ebay in masses what seems like a few years ago, through a single source. I have never held one in person, so I can't comment as to the actual quality of them, but there is a lot of haziness to them and other cards similar to them that have been passed off as something they were not, to eager collectors wanting new items of their favorite players and willing to bid against each other w/o knowing what they were buying. The lines between a legitimate licensed vintage issue that most people have never seen or heard of and "custom" cards that appear to be old but are not are blurring further by the day. I have been on ebay since 1998 and I can't say I ever ran across any before a few years ago.
I just found this card recently. Searching ebay for new Garvey items nearly daily for 20+ years and this card, shown as made in 2000, pops up for the first time ever as far as I have seen, 20 years after it was made. I'd say based on the description you have given about Miller Press, this cards falls into the same category. It was clearly made by a printing company, but I know no more than I can see from the card. I'd still consider this "handmade" and not produced by a company on large scale for the masses.