dermaroller- what length for everyday use?

[Memnon]

I'm interested in trying a dermaroller, mainly to increase the absorption of minoxidil, particularly on the frontal scalp. However most of the research shows results with a 1.5mm needle, used only once weekly; more frequent use may result in damage or pain in the scalp. This seems counterintuitive to my planned use of it, as I mainly want to use it to increase the absorption of my daily minoxidil application. Using the needle only once weekly may make this futile, as the microneedle 'holes' close up after only an hour or so, doesn't it? You have to apply the minoxidil right after using the needle/roller, don't you?

So what length of needle should I consider if I want to use it daily for it's minoxidil-boosting benefits? A smaller length like 0.5 or .075mm? Would 1.0mm probably be too long for daily use?