Hard to say how long. I had a couple trial runs but all in all I'd say I spent about 3 hours in actual hands-on modding work. I used

XOOL 151 PCS Watch Repair Kit... https://www.amazon.com/dp/B07Z8SC4GL?ref=ppx_pop_mob_ap_share

It was ok. You get what you pay for and this wasn't much, but I made it work.