Hey Mike, welcome! Glad you're here and we'd like to see ya around a lot longer! I'm a little concerned about your predicament here. Reading between the lines, sounds like you'd like to avoid the cost of having the mast lowered by a yard and you're looking for a safe do-it-yourself alternative. OK, so the prior posts have made it clear you could be risking your life if you don't handle this situation properly - true enough so ya gotta pay attention to that. Plus, ya really don't wanna wreck your mast by drilling unnecessary holes in it.
Whatever else though . . . don't attempt to climb the mast without proper gear and a backup - find another solution. I second Fordo's caution: do not trust the attachment point a topping lift block is connected to or the block itself with your life. You don't know how strong it really is and there is a single point of failure risk - one thing breaks . . . maybe you're gone or seriously injured for life - this stuff really happens!
Maybe you haven't received more/better alternative suggestions from the experts here on Sailnet because there aren't too many other good choices for this case (some, possibly involving help from neighbors with taller masts entail property damage risk to your boat and the neighbor's boat, so other sailors might be reluctant to try it). Like brakes on a car - ya just don't skimp on certain key items if you'd like to stick around on this planet a little longer. Maybe suck it up on this one and find a way to pay to have this particular job done safely by a boat yard with proper equipment.