A question about Capt Laidler's elevation "roughing" technique to mount a No32 scop

He says to aim at a DAP (distance aiming point) of 250 yards, with the scope set to 250 yards elevation.

Unfortunately, I'm in a pretty built up area and cannot see 250 yards out of any of my windows without having an obstacle in my way.

I was wondering if I I measure 28 feet from my kitchen into my garage and hang a target and do the classroom zeroing will I be OK?

IE bore site a target @ 28 feet, then put a dot 1.8 inches above it, then swing my mount up and down until my "grat" is dead on the mark (with the elevation set to zero of course).
Then fix the rear pad?

If the 28 feet method was any good, the snipers wouldn't need to waste time on the ranges zeroing in properly. It is a rough and ready method

If you haven't got 250 yards over which to use the DAP method, then I suggest that you do what everyone else does. Take the rifle out to somewhere that you can make 250 yards is my opinion. What about on the rifle range. Then when you've done it, it's just a short walk back to 300 and zero it in with live ammo

I haven't mounted the rear pad yet, this is to get the rough elevation prior to drilling and tapping.

You didn't say that! But in your case, it is important that you do it at this distance................